Vehicular turning seat

ABSTRACT

A rotating vehicle seat allows space close to an occupant&#39;s feet to be used efficiently. The rotating seat has a seat body  2  supported by a rotary disc  13.  The rotary disc  13  is mounted at a position that is displaced to a door opening side with respect to a center HP of a seat cushion. A pinion gear  6,  an intermediate gear  36  and a rack  38  engage each other so that the rotational movement and the longitudinal movement of the seat body  2  are coupled to each other.

FIELD OF THE INVENTION

The present invention relates to rotating vehicle seats that aredesigned so that passengers, such as elderly or handicapped persons, caneasily get in or out of a vehicle.

BACKGROUND OF THE INVENTION

A rotating seat of this type has been constructed to be rotated to theside of a door opening with an occupant held in a seated position (asdisclosed, for example, in Japanese Laid-Open Utility Model PublicationNo. 61-57047 and Japanese Laid-Open Patent Publication No. 62-173343).The rotating vehicle seat is typically disposed as far to the rear aspossible in order to provide a wide space close to the occupant's feet.Therefore, the seats in the front and the rear, for example in afour-door sedan car, are disposed such that the seats are masked besidethe center pillars and the rear pillars.

Therefore, if the seat is rotated while in the initial seated position,the pillar that is positioned beside the seat interferes with therotation of the seat to the entry/exit position. Therefore, with theknown rotating seat, the rotating seat is first moved forward in orderto be moved outside of the range of interference with the pillar.Thereafter, the seat is rotated to the door opening side.

DISCLOSURE OF THE INVENTION

Thus, the known rotating seat is inconvenient to use because it requirestroublesome operations of moving the rotating seat forward and thenrotating it to the side of the door opening. Further, if the seat ispositioned near the front, such that the seat can be rotated while inthe seated position, the space close to occupant's feet will besacrificed and the occupant will be forced to sit in an uncomfortableposition.

The present invention has been made in view of the above problems, andits object is to provide a rotating vehicle seat that is convenient touse without sacrificing the space close to the occupant's feet.

To this end, the invention according to claim 1 provides a rotatingvehicle seat that comprises a rotating support base for supporting aseat body in a manner that permits rotation around a center of rotationthat is located at a point displaced to a door opening side with respectto a center of a seat cushion, a longitudinal support base forsupporting the rotating support base to permit movement in alongitudinal direction of the vehicle, and coupling means for couplingthe rotational movement and the longitudinal movement of the seat body,the coupling means including a pinion gear mounted beneath the seat bodyto the interior side of the center of rotation and a rack mounted on andextending in a longitudinal direction of the longitudinal support base,the rack engaging the pinion gear via an intermediate gear.

According to this rotating vehicle seat, when the seat body is rotatedto the door opening side by means of the rotating support base, the seatbody moves forward while rotating by engagement between the pinion gearand the rack via the intermediate gear. Therefore, even if the seat bodyis located in the rearmost position in order to provide a wide spaceclose to the occupant's feet, the seat body can rotate by a simplerotational operation to the door opening side without interfering with apillar or other portions of the vehicle. In other words, unlike theknown rotating seat, it is not necessary to perform two operations ofrotating the seat body and moving the seat body forward. Consequently,with the rotating vehicle seat according to claim 1 of the invention, itis possible to greatly improve ease of use while providing a wider spaceclose to the occupant's feet.

Further, because the center of rotation of the seat body is located at apoint that is displaced to a door opening side with respect to thecenter (HP: hip point) of the seat cushion, a pinion gear having alarger diameter can be mounted under the seat body to the interior sidewith respect to the center of rotation. Because the pinion gear having alarger diameter has a larger circumferential length, the distance of thelongitudinal movement of the seat body, which is coupled to therotational movement of the seat body, can be longer. Thus, the seat bodycan be moved a longer distance while rotating, for example, by about90°. Therefore, the seated position of this rotating seat can bepositioned more rearward so as to provide a wider space close to theoccupant's feet, so that this rotating seat can be reasonably applied tovarious types of vehicles.

The pinion gear having a larger diameter can be also mounted to the dooropening side with respect to the center of rotation when the center ofrotation of the seat body (rotating support base) is located to theinterior side with respect to the center of the seat cushion. In thiscase, however, when the seat body is rotated to the door opening side,the center of the seat cushion is displaced rearward. Therefore, thecenter of rotation, which is located more to the interior side, makes itmore difficult to move the center of the seat cushion a long distanceforward. In this respect, with the construction according to claim 1,because the center of rotation is located to the door opening side withrespect to the center of the seat cushion, the moving distance of thecenter of the seat cushion is a total of the forward displacement by therotation of the seat body plus the forward moving distance of therotating support base. Therefore, the center of the seat cushion can bemoved a longer distance forward.

The invention according to claim 2 provides the rotating vehicle seat asdefined in claim 1, further comprising a lateral support base for movingthe seat body in a lateral direction of the vehicle and a stopper memberfor preventing longitudinal movement of the seat body during lateralmovement of the seat body, wherein the stopper member is disposed on thelongitudinal support base to permit movement into and out of alongitudinal travelling path of the seat body, such that the stoppermember moves out of the travelling path of the seat body to therebyallow the seat body to move longitudinally when the longitudinal supportbase is moved to an interior side end of the lateral support base, whilethe stopper member moves into the travelling path of the seat body tothereby prevent longitudinal movement of seat body when the longitudinalsupport base moves from the interior side end to the exterior side ofthe lateral support base.

According to this rotating vehicle seat, unlike the known rotating seat,a stopper member for restricting the longitudinal movement of the seatbody is disposed on the longitudinal support base and not on the lateralsupport base. Therefore, whether the longitudinal support base is movedby the lateral support base in a horizontal direction, or in aninclining direction as the known rotating seat, the seat body can beprevented from moving longitudinally while moving laterally with respectto the vehicle.

Further, in the known rotating seat, the stopper means was provided onthe lateral support base and thus required a size change according tothe lateral moving distance of the longitudinal support base, which isnot desirable for simplifying the construction or reducing the weight ofthe present rotating vehicle seat. With the construction according toclaim 2, because the stopper member is provided on the longitudinalsupport base that moves laterally, the construction can be made compactirrespective of the lateral moving distance of the longitudinal supportbase, and thus the weight can be reduced.

The invention according to claim 3 provides the rotating vehicle seat asdefined in claim 1, further comprising a lateral support base for movingthe seat body in a lateral direction of the vehicle, the lateral supportbase being disposed between the rotating support base and the seat bodyand being constructed to move the seat body to a lower position as theseat body moves to the outside in the lateral direction of the vehicle.

According to this rotating vehicle seat, because the lateral supportbase is rotated by the rotating support base, unlike a known lateralsupport base, the lateral support base moves to a position in which itslongitudinal sides extend in the longitudinal direction of the vehicle.Therefore, when the rotating vehicle seat of this invention is appliedto a passenger's seat, a wider space can be provided between thepassenger's seat and the driver's seat. Further, even if the motor isdisposed on the rear end of the lateral support base in a manner toprotrude from the lateral support base, the motor is moved to a positionfacing the rear seat. In this respect also, a wider space can beprovided between the passenger's seat and the driver's seat. Thus, thespace can be effectively utilized for various purposes, such as apassage to the rear seats.

The invention according to claim 4 provides the rotating vehicle seat asdefined in claim 3, wherein the seat body can be detached from thelateral support base so as to be used as a wheelchair.

According to this rotating vehicle seat, the seat body can be-usedseparately as a wheelchair outside the vehicle, and when the seat bodyis connected as is to a lateral support base and moved into the vehicle,it can be also used as a passenger seat. Such a rotating seat does notrequire the wheelchair user to change from a vehicle seat inside thevehicle to a wheelchair outside the vehicle and vice versa, therebymaking it easier for such a wheelchair user to enter and exit a vehicle.

Further, because the seat body can be used separately as a wheelchairand can be moved into the vehicle while maintaining the wheelchairfunction, the rotating seat is more convenient to use, compared withknown rotating seats in which a wheelchair frame portion must bedetached to use the seat body inside the vehicle.

Further, after having been used as a wheelchair, the seat body can beconnected to the lateral support base by superposing and connecting theconnecting base of the seat body on the inclined base. The inclined baseis downwardly inclined toward the exterior side, and the connecting baseis disposed parallel to the inclined base. With this construction,differences in the vertical position between the seat body and thelateral support base, if any, existing in the stage of moving the seatbody as a wheelchair toward the lateral support base can be corrected bysliding contact between the connecting base and the inclined base thatare parallel to each other. As a result, the seat body can be easilyconnected to the lateral support base.

On the contrary, in a known rotating seat, for example, a wheelchair isseparated into a seat portion and a frame portion and only the seatportion is moved into a vehicle and used as a seat body. In order tomove the seat body as a seat portion of the wheel chair, the seat bodyis moved along and between rails on the wheelchair frame and rails onthe vehicle floor. In such a case, the vertical position of the rails onthe wheelchair frame is required to correspond to the rails on thevehicle floor, and the difference in the vertical position of the seatbody is not corrected, thereby requiring troublesome work in connectingthe seat body.

The invention according to claim 5 provides the rotating vehicle seat asdefined in claim 3, wherein the longitudinal support base and/or thelateral support base has a linear slide mechanism that consists of anouter rail, an inner rail and a plurality of steel balls disposedbetween the rails.

According to this rotating vehicle seat, the position of the fixed sideor the moving side or both of one or both of the left and right linearslide mechanisms is adjusted in a direction perpendicular to the slidingdirection. Thus, the force of pushing the steel balls 220 c by the fixedrail and the moving rail in the linear slide mechanism 220 can beadjusted. Because a plurality of the steel balls are disposed betweenthe V-shaped grooves, with the construction in which the fixed rail andthe moving rail relatively push each other by an appropriate force,vertical and horizontal relative rattling of the rails can be prevented.As a result, the lateral support base and/or the longitudinal supportbase can slide smoothly without rattling.

The invention according to claim 6 provides the rotating vehicle seat asdefined in claim 1, further comprising a swing extending mechanism thatessentially consists of a quadric link mechanism, wherein the seat bodycan be moved laterally with respect to the vehicle by the swingextending mechanism and wherein the seat body can be detached from theswing extending mechanism so as to be used as a wheelchair.

According to this rotating vehicle seat, a wheelchair user can get in orout of the vehicle while he or she remains sitting in the wheelchair.Further, after the wheelchair user gets out of the vehicle while he orshe remains sitting in the wheelchair inside the vehicle, the wheelchaircan be detached from the lift-up mechanism and used in the same manneras a normal wheelchair. Therefore, unlike a known rotating seat, thewheelchair user does not need to change from a vehicle seat to awheelchair or vice versa in the outside of the vehicle when getting intoor out of the vehicle, thereby making such a wheelchair more convenientto use.

Particularly, the wheelchair can be connected as a whole, keeping theseat frame and the wheels as well as the seat section, to the lift-upmechanism so as to be moved between the inside and the outside of thevehicle. Therefore, the wheelchair user or the helper is only requiredto perform a simple operation of connecting the lift-up mechanism.Additional operations, such as separating the wheelchair into the seatsection and the frame section, are not required. Also in this respect,such a wheelchair is more convenient to use.

Further, with a known construction in which the wheelchair is separatedinto the seat section and the frame section and only the seat section ismoved into the vehicle, it is necessary to load the separated framesection separately into the vehicle. However, such labor is notnecessary with a construction as described in claim 6 in which the wholewheelchair is moved and installed in the vehicle compartment. Also inthis respect, the wheelchair is convenient to use, particularly forpassengers' helpers, and the usability of the vehicle rotating seat canbe improved.

In this specification, retaining the sitting attitude of the wheelchairmeans to retain the attitude of the wheelchair on the road. The attitudeof the wheelchair means the attitude (orientation) of the wheelchair inwhich the wheelchair user sitting in the wheelchair can retain thesitting attitude comfortably without falling down or otherwise beinginjured.

Further, the state in which the vehicle chair “can be used separately”as a wheel chair refers to the state in which the vehicle chair has atleast a seat section (seat body) and travelling wheels and can be usedas a normal wheelchair.

The invention according to claim 7 provides the rotating vehicle seat asdefined in claim 1, further comprising a swing extending mechanism thatessentially consists of a quadric link mechanism, wherein the seat bodycan be moved laterally with respect to the vehicle by the swingextending mechanism and wherein the seat body can be detached from theswing extending mechanism so as to be used as a seat of a wheelchair.

According to this rotating vehicle seat, the seat holder with the seatbody mounted thereon, can be moved by the lift-up mechanism from thevehicle compartment floor to the outside of the vehicle and vice versa,and can function as a seat section of the wheelchair when detached fromthe lift-up mechanism. Therefore, while sitting in the seat body, thepassenger can move with the seat holder onto the seat frame of thewheelchair which is standing by outside the vehicle. Also, the passengercan move with the seat holder from the wheelchair into the vehicle whilesitting in the seat body. As a result, the passenger's helper does notneed to help the passenger to transfer from and to the wheelchair, sothat the labor of the helper can be greatly reduced.

Further, because the seat body forms the seat section of the wheelchairtogether with the seat holder, the ride comfort of the wheelchair can beimproved.

Additionally, the connecting and disconnecting structure of the seatholder is very simple in construction, which consists of the seatholder, the anchor plates, the lock bolts and the lock knobs. Therefore,such a structure can be readily applied to existing lift-up mechanisms.

The invention according to claim 8 provides the rotating vehicle seat asdefined in claim 1, further comprising a swing extending mechanism thatessentially consists of a quadric link mechanism, wherein the seat bodycan be moved laterally with respect to the vehicle by the swingextending mechanism and wherein an electric motor is used as a drivingsource for the swing extending mechanism, the motor having a threadedshaft oriented to the front of the seat.

According to this rotating vehicle seat, the threaded shaft of the ballscrew is not directed to the rear of the seat, so that the threadedshaft is not offensive to an occupant sitting in a seat that is behindthe rotating seat. With this construction, when the electric motor ofthe actuator is actuated, the threaded shaft is rotated and the nut ismoved relatively with respect to the threaded shaft. However, becausethe nut is connected to the vehicle floor side, the threaded shaft andthus the actuator eventually move themselves and the quadric linkmechanisms are extended and retracted.

The invention according to claim 9 provides the rotating vehicle seat asdefined in claim 1, further comprising a swing extending mechanism thatessentially consists of a quadric link mechanism, wherein the seat bodycan be moved laterally with respect to the vehicle by the swingextending mechanism, and further comprising a swing lock mechanism thatfunctions only when an impact is applied while the vehicle is running,so as to prevent the seat body from moving forward with respect to thevehicle by the swing extending mechanism, while, in normal operationswhen the vehicle is stopped, permitting the seat body to be movedlaterally with respect to the vehicle.

With this rotating vehicle seat, when a strong impact is exerted on thevehicle by abrupt deceleration of the vehicle, swinging movement of theseat body is prevented by the swing lock mechanism.

In the normal extending operations when the vehicle is stopped, if theswing extending mechanism is actuated to start to slowly extend the seatbody to the outside, the swing lock mechanism is released by couplingwith the movement of the seat body. On the other hand, in the process ofreturning the seat body from the exterior side to the interior side bythe reverse swinging movement of the swing extending mechanism, theswing lock mechanism is automatically locked when the seat body has beenreturned to a predetermined position in the vehicle. Thus, by couplingwith the swinging movement of the seat body, the swing lock mechanism isautomatically locked and unlocked. The swing locked state can bemaintained irrespective of the sliding position by the slide mechanismwhich is separately set as necessary. Therefore, while maintaining theswing locked state, the position of the seat body in the longitudinaldirection of the vehicle can be adjusted by utilizing the slidemechanism.

Further, when abrupt impact is exerted on the seat body, the swinglocked state can be maintained, so that the load onto the seat body canbe transmitted to the vehicle floor.

Further, because the swing locked state can be maintained irrespectiveof the lateral sliding position, the swing lock mechanism of thisembodiment can be applied irrespective of whether a lateral slidemechanism is provided or not.

The invention according to claim 10 provides the rotating vehicle seatas defined in claim 1, further comprising a swing extending mechanismthat essentially consists of a quadric link mechanism, wherein the seatbody can be moved laterally with respect to the vehicle by the swingextending mechanism, and further comprising a swing lock mechanism thatfunctions to prevent the seat body from being moved forward with respectto the vehicle by the swing extending mechanism when the seat body islocated in a position facing the front of the vehicle, while permittingthe seat body to be moved laterally with respect to the vehicle by theswing extending mechanism when the seat body is rotated to the dooropening side.

With this rotating vehicle seat, when the seat body is rotated to theposition facing the front of the vehicle, the swing lock mechanism islocked by being coupled to this rotational movement of the seat body.And when the seat body starts to rotate to the door opening side, theswing lock mechanism is automatically unlocked by coupling with thisrotational movement of the seat body. Thus, the swing lock mechanism islocked and unlocked by coupling with the rotational movement of the seatbody. Therefore, unlike a known rotating seat, the users do not need tomanually operate the swing lock mechanism, so that the usability of therotating vehicle seat of this embodiment can be improved.

Further, the lock holder is engaged with the lock plate by physicalengagement between the lock holder and the anchor hook. Therefore, aslong as the seat body is held in the position facing the front of thevehicle, the seat body can be reliably maintained in the swing lockedstate, even in the event of occurrences generating a large impact orvibrations. However, if it is constructed, for example, such that abiasing force of a spring is used to maintain the engagement of the lockholder with the lock plate, when a strong impact or vibrations areexerted on the vehicle, the lock holder may be rotated against thebiasing force of the spring by the inertial force, so that the swinglock may be released. With the construction of the invention asdescribed in claim 10, there is no possibility of such occurrences.

The invention according to claim 11 provides the rotating vehicle seatas defined in claim 1, wherein the longitudinal support base includes alinear slide mechanism that consists of a fixed rail, a moving rail anda plurality of rolling elements disposed between the fixed rail and themoving rail, and wherein a guide rail is provided on and along one sideof the moving rail, which is opposite to the side of the fixed rail andsupports the moving rail to permit the moving rail to slide.

With this rotating vehicle seat, a guard rail is provided on and alongthe inner side of the inner rail in parallel to the outer rail to permitthe inner rail to slide. Thus, the deformation of the inner rail can beminimized and the removal of the rolling elements can be prevented, sothat the longitudinal movement of the linear guide mechanism can bemaintained with stability.

The invention according to claim 12 provides the rotating vehicle seatas defined in claim 11, further including a hook that is provided on atravelling path of the moving rail such that a rear end portion of themoving rail can slide into and out of the hook.

With this rotating vehicle seat, the inner rails can be prevented frombeing raised by a belt load that will act on the seat belt in the eventof hard braking or a collision when the vehicle is running. Further, thebelt load can be absorbed via the hook to the floor side, so damage tothe linear guide mechanism can be prevented.

The invention according to claim 13 provides the rotating vehicle seatas defined in claim 1, wherein a toothless portion is formed on aninitial engagement portion of the intermediate gear and a deformed toothis formed on an initial engagement portion of the pinion gear andengages the toothless portion, the deformed tooth having a thicknesssubstantially corresponding to a length of the toothless portion, aheight of the deformed tooth on a front end in a direction of startingengagement being smaller than normal teeth, and a height of the deformedtooth on a rear end in the direction of starting engagement being equalto normal teeth.

With this rotating vehicle seat, when the seat body is rotated to thedoor opening side (in the engagement starting direction), at the stagewhen the pinion gear starts to engage the intermediate gear, that is,when shifting from the non-coupling state to the coupling state, becausethe deformed tooth of the pinion gear first engages the intermediategear and the height of the deformed tooth on the front end in theengagement starting direction is smaller than normal teeth, the deformedtooth engages the toothless portion of the intermediate gear withoutinterfering with the tooth on the rearward side of the toothless portionin the engagement starting direction. Thus, the pinion gear smoothlyengages the intermediate gear.

On the other hand, when the seat body rotates from the door opening sideto the interior side to be returned to the position facing to the frontof the vehicle (when rotated in the direction opposite to the engagementstarting direction), at the stage of finishing the engagement betweenthe pinion gear and the intermediate gear, that is, when shifting fromthe coupling state to the non-coupling state, because the deformed toothof the pinion gear last engages the intermediate gear and the height ofthe deformed tooth on the rear end in the engagement starting directionis equal to normal teeth. Thus, the pinion gear securely engages theintermediate gear. Therefore, the engagement (coupling state) betweenthe pinion gear and the intermediate gear is maintained all the way, andthus the seat body can be reliably returned to the rear end slidingposition.

Further, because the seat body can be reliably returned to the rear endsliding position, in the case of using a slide lock mechanism that iscoupled to the rotational movement of the seat body, the slide lockmechanism can function properly and reliably.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a vehicle, showing a position of a rotatingseat in the vehicle;

FIG. 2 is a perspective view of a seat body;

FIG. 3 is a perspective view of a lift-up mechanism;

FIG. 4 is a perspective view of a rotating support base and alongitudinal support base;

FIG. 5 is a perspective view of an actuator;

FIG. 6 is a plan view of coupling means for coupling a rotationalmovement and a longitudinal movement of the seat body;

FIG. 7 is a perspective view of a rotation lock mechanism;

FIG. 8 is a perspective view of coupling means for coupling rotationalmovement and longitudinal movement of the seat body and a slide lockmechanism;

FIG. 9 is a sectional view of the slide lock mechanism in (a) the stateof slide lock, in (b) the moving state of a retainer and in (c) thestate of slide lock release;

FIG. 10 is sectional view of a linear guide mechanism, taken along line(10)—(10) in FIG. 8;

FIG. 11(A) is a plan view of the seat body, illustrating the movement ofthe rotating vehicle seat of the first embodiment and showing the seatbody in a seated positions,

FIG. 11(B) is a plan view of the seat body, illustrating the movement ofthe rotating vehicle seat of the first embodiment and showing the seatbody rotated by about 40° to the door opening side;

FIG. 11(C) is a plan view of the seat body, illustrating the movement ofthe rotating vehicle seat of the first embodiment and showing the seatbody in a sideways position;

FIG. 11(D) is a plan view of the seat body, illustrating the movement ofthe rotating vehicle seat of the first embodiment and showing the seatbody moved to the exterior;

FIG. 12 is a side view of a lift-up mechanism, in which an actuator isarranged to have a gear box on the rear;

FIG. 13 is a side view of a lift-up mechanism, in which an actuator isarranged to have a threaded shaft on the rear;

FIG. 14 is a perspective view of a longitudinal support base accordingto an embodiment of the invention as described in claim 2 (a secondembodiment);

FIG. 15 is a sectional view taken along line I—I in FIG. 16.

FIG. 16 is a side view of a restricting arrangement that is connected toa main frame of a longitudinal support base that is slidably mounted ona horizontally disposed lateral support base;

FIG. 17 is a side view of the seat body, illustrating its horizontalmovement from the inside to the outside of the vehicle;

FIG. 18 is a side view of a restricting arrangement that is connected toa main frame of a longitudinal support base that is slidably mounted onan obliquely disposed lateral support base;

FIG. 19 is a side view showing the positional relationship of a stoppermember with the seat base, the rotating support base and thelongitudinal support base in each operational position;

FIG. 20 is a plan view showing the positional relationship of thestopper member with the seat base and the rotating support base in eachoperational position;

FIG. 21 is a view showing an embodiment of the invention as described inclaim 3 (a third embodiment), in which a passenger's seat as a rotatingvehicle seat and a driver's seat are shown as viewed from the rear ofthe vehicle, and in which the seat body of the rotating vehicle seat isshown in a position facing the front of the vehicle;

FIG. 22 is also a view of the rotating vehicle seat and the driver'sseat as viewed from the rear of the vehicle, in which the seat body ofthe rotating vehicle seat is shown in a position facing the door openingside and the seat body is shown sliding in the lateral direction of thevehicle;

FIG. 23 is a perspective view of the seat body;

FIG. 24 is a perspective view of a seat holder;

FIG. 25 is a perspective view of a lateral support base;

FIG. 26 is sectional view taken along line A—A in FIG. 25, showing aposition adjusting mechanism provided on the rear of a fixed rail;

FIG. 27 is sectional view taken along line B—B in FIG. 25, showing aposition adjusting mechanism provided around the medial portion of thefixed rail;

FIG. 28 is sectional view taken along line C—C in FIG. 25, showing aposition adjusting mechanism provided on the front of the fixed rail;

FIG. 29 is a perspective view of a rotating support base and alongitudinal support base;

FIG. 30 is a plan view of coupling means for coupling longitudinalsliding movement and rotational movement to a door opening side of theseat body;

FIG. 31 is a front view of a lateral support base incorporating a knownlinear slide mechanism;

FIG. 32 is a front view of the lateral support base incorporating theknown linear slide mechanism, including a mechanism for minimizinghorizontal rattling;

FIG. 33 is a perspective view showing an embodiment of the invention, inwhich a seat body is shown detached from a lift-up mechanism;

FIG. 34 is also a perspective view showing the embodiment of theinvention, in which the seat body is shown being connected to thelift-up mechanism and moved into the vehicle;

FIG. 35 is a side view of the seat body connected to an inclined base ofthe lift-up mechanism, in which a solid line depicts a wheel frame in anextended state and a broken line depicts the wheel frame in a storedstate;

FIG. 36 is a perspective view of a connecting base;

FIG. 37 is a perspective view of a lateral support base;

FIG. 38 is a underside view of the inclined base;

FIG. 39 is sectional view taken along line (7)—(7) in FIG. 37;

FIG. 40 is a perspective view of a rotating support base and alongitudinal support base;

FIG. 41 is a perspective view showing an embodiment of the invention, inwhich a wheelchair is shown detached from a lift-up mechanism;

FIG. 42 is also a perspective view showing the embodiment of theinvention, in which the wheelchair is shown connected to the lift-upmechanism and lifted up above the ground;

FIG. 43 is a side view of the rotating vehicle seat, showing aconnecting mechanism for connecting the lift-up mechanism to thewheelchair;

FIG. 44 is sectional view taken along line A—A in FIG. 43, showing aconnecting plate inserted into a connecting recess;

FIG. 45 is a side view showing an upper end of the connecting plateengaged into a catching recess of the connecting recess;

FIG. 46 is a side view showing the supporting state of a lock lever 25;

FIG. 47 is a perspective view of the entire lift-up mechanism;

FIG. 48 is a perspective view of an entire electric cylinder;

FIG. 49 is a plan view of coupling means for coupling a rotationalmovement of a swing base and a sliding movement of a main base;

FIG. 50 is a side view of a lock bar of a coupled locking type andcomponents therearound;

FIG. 51 is a perspective view of a lift-up mechanism according to asixth embodiment of the invention;

FIG. 52 is a perspective view of a seat holder with a seat body mountedthereon, which is shown separated from the distal ends of the quadriclink mechanisms;

FIG. 53 is sectional view taken along line B—B in FIG. 52;

FIG. 54 is a side view illustrating a relation between the wheelchairand the seat holder with the seat body mounted thereon;

FIG. 55 is a side view of a rotating vehicle seat according to a seventhembodiment of the invention, in which the right-left direction as viewedin the drawing corresponds to the lateral direction with respect to thevehicle;

FIG. 56 is a perspective view of an entire swing lock mechanism, inwhich a seat holder and a swing base are not shown;

FIG. 57 is a side view of the swing lock mechanism in the locked state;

FIG. 58 is a side view of the swing lock mechanism in the unlockedstate;

FIG. 59 is a side view of the swing lock mechanism in the unlockedstate, with seat body being in the extended position outside thevehicle;

FIG. 60 is a side view of the rotating vehicle seat, in which lateralslide rails are utilizes as longitudinal slide rails.

FIG. 61 is a side view of a modification of a swing lock mechanism inthe seventh embodiment;

FIG. 62 is a schematic plan view of a vehicle having a rotating vehicleseat according to an eighth embodiment of the invention;

FIG. 63 is a side view of the rotating vehicle seat according to theeighth embodiment;

FIG. 64 is a perspective view of a swing lock mechanism;

FIG. 65 is a side view of the swing lock mechanism;

FIG. 66 is an end view of the swing lock mechanism;

FIG. 67 is a plan view showing the positional relationship between thecenter of rotation of the seat body (which is also the center ofrotation of the seat holder and the swing base and is the samethroughout this specification) and the center of gravity of the seatbody, in which a seat body and a seat holder are shown;

FIG. 68 is also a plan view showing the positional relationship betweenthe center of rotation and the center of gravity of the seat body, inwhich the seat body and the seat holder are removed and a swing base isshown;

FIG. 69 is a plan view showing a ninth embodiment of the invention, inwhich a mechanism for coupling the rotational movement and thelongitudinal movement of the seat body is shown;

FIG. 70 is a sectional view of linear slide mechanisms of thelongitudinal support base and the rotating support base;

FIG. 71 is a perspective view of rear portions of the longitudinalsupport base and the rotating support base;

FIG. 72 is a sectional view illustrating a relationship between an innerrail and a hook;

FIG. 73 is a side view of a known rotating vehicle seat;

FIG. 74 is a plan view of a seat stand and components therearound;

FIG. 75 is a sectional view illustrating an engagement between a seatslide rail and a hook racket;

FIG. 76 is a plan view of a pinion gear, an intermediate gear and a rackat the beginning of engagement of a rotation/slide coupling mechanism;

FIG. 77 is an enlarged view of a deformed tooth of the pinion gear;

FIG. 78 is a plan view of a pinion gear, an intermediate gear and a rackat the end of engagement of the rotation/slide coupling mechanism;

FIG. 79 is a plan view showing engagement between a backlash preventiontooth and the intermediate gear;

FIG. 80 is a perspective view of a rotation/slide coupling mechanism anda slide lock mechanism;

FIG. 81 a plan view of a known rotation/slide coupling mechanism;

FIG. 82 is a plan view showing engagement between a pinion gear and theintermediate gear in the known rotation/slide coupling mechanism;

FIG. 83 is a view of a known rotating vehicle seat and a driver's seatas viewed from the rear of the vehicle, which is shown in relation tothe third embodiment;

FIG. 84 is a plan view of vehicle compartment with the known rotatingvehicle seat applied to a passenger's seat, which is also shown inrelation to the third embodiment.

BEST MODES FOR PERFORMING THE INVENTION

An embodiment of the present invention as defined in claim 1 (a firstembodiment) will now be explained with reference to FIGS. 1 to 13. Arotating vehicle seat 1 (hereinafter referred to as a “rotating seat” aswell) according to the first embodiment will be described as an exampleof application of a passenger's seat on the left of a driver's seat asshown in FIG. 1. The rotating seat 1 can be rotated by about 90° to theleft (or counterclockwise) as viewed in FIG. 1 in order to move to theoutside of a vehicle through a door opening D on the left of therotating seat 1.

The rotating seat according to the first embodiment includes a seat body2, a lift-up mechanism 50 for moving the seat body 2 laterally withrespect to the vehicle (from the inside to the outside of the vehicleand vice versa), a rotating support base 10 for rotatably supporting theseat body 2 and the lift-up mechanism 50, and a longitudinal supportbase 30 for moving the seat body 2, the lift-up mechanism 50 and therotating support base 10 longitudinally with respect to the vehicle. Theseat body 2 and the lift-up mechanism 50 are shown in detail in FIGS. 2and 3, and the rotating support base 10 and the longitudinal supportbase 30 are shown in detail in FIG. 4. In the drawings, the front of thevehicle is shown by a “forward” arrow, and the side having a dooropening is shown by an “outside” arrow.

As shown in FIG. 2, the seat body 2 has a seat cushion 2 a and a seatback 2 b, and a footrest 2 c for resting the occupant's feet thereon ismounted to the front of the seat cushion 2 a. The seat body 2 is of aknown type and has not been particularly modified to achieve thisinvention.

The seat body 2 is mounted on the lift-up mechanism 50. As shown in FIG.3, the lift-up mechanism 50 essentially consists of a pair of quadriclink mechanisms 55. The lift-up mechanism 50 serves to move the seatbody 2 from the inside to the outside of the vehicle and vice versa byextending and retracting the pair of quadric link mechanisms. Designatedby numeral 53 is a base for the lift-up mechanism 50. The base 53includes a bottom 53 b and two side walls 53 a extending verticallyupwardly from both sides of the bottom 53 b. Each of the quadric linkmechanisms has a first link arm 51 and a second link arm 52. The linkarms 51 and 52 are connected to the side walls 53 a through pivots 51 aand 52 a, respectively, for pivotal longitudinal movement with respectto the vehicle body. The rear second link arms 52 are connected byconnecting rods 54, 55 and pivot together. The ends of the lowerconnecting rods 54 are rotatably supported with respect the side walls53 a of the base 53 and thus the axis of the connecting rod 54 forms thepivotal fulcrum or pivot 52 a of the second link arm 52.

The distal ends of the first and second link arms 51 and 52 areconnected by a connecting arm 56 and an extending arm 57. The link arms51 and 52 are rotatably connected through pivots 51 b and 52 b,respectively, with respect to the connecting arm 56 and the extendingarm 57. The side wall 53 a, the first link arm 51, the second link arm52 and the extending arm 57 forms the quadric link mechanism.

Each of the extending arms 57 is generally L-shaped and extends forward.As shown in FIG. 3, a flange 57 a is formed on the front end portion ofthe arm 57 and extends inwardly. Both front ends of the arms 57 arcconnected by a reinforcing bar 58. The seat body 2 is mounted on bothflanges 57 a and the reinforcing bar 58 and is fixed by bolts (notshown).

Two L-shaped support arms 59 are fixed in a generally medial portion ofthe lower connecting rod 54. An actuator 60 is mounted between thequadric link mechanisms and the vehicle floor by the support arms 59 andserves as a driving source for the lift-up mechanism 50. As shown inFIG. 5, the actuator 60 essentially consists of an electric motor 61, agear box 62 and a ball screw 63. The ball screw 63 includes a threadedshaft 63 a and a block-shaped nut 63 b threadably engaged with thethreaded shaft 63 a. When the motor 61 is started, the threaded shaft 63a rotates by torque amplified by means of the gear box 62 and thus thenut 63 b moves axially with respect to the threaded shaft 63 a.

The threaded shaft 63 a is rotatably supported by a cylindrical threadedshaft case 63 c mounted on the output shaft side of the gear box 62. Thethreaded shaft case 63 c is supported by the support arms 59 via thepivots 59 a for vertical pivotal movement. Further, plate-like brackets63 d are mounted on both side surfaces of the nut 63 b. A front end ofeach of the brackets 63 d is connected by a shaft 64 to an upper surfaceof the bottom 53 b of the base 53 near a front end thereof so as topermit vertical pivotal movement. In the first embodiment, as describedabove, the actuator 60 is assembled in an orientation to locate thethreaded shaft 63 a at the front of the seat body 2 and to locate thegear box 62 at the back of the seat body 2.

With the actuator 60 thus assembled, when the motor 61 is rotated in aforward direction with the seat body 2 being held facing the dooropening side as will be described below, the threaded shaft 63 a rotatesand thus the nut 63 b moves relative to the threaded shaft 63 a towardthe front end of the threaded shaft 63 a. However, because the nut 63 bcan pivot vertically but cannot move longitudinally with respect to theseat body 2 (laterally with respect to the vehicle in this stage), thethreaded shaft 63 a and thus the actuator 60 move rearward of the seatbody 2. This state is shown in FIG. 12. When the actuator 60 (excludingthe nut 63 b) moves rearward, the support arms 59 and the connecting rod54 rotates counterclockwise as viewed in FIG. 3. As a result, the secondlink arms 52 pivot about the pivots 52 a toward the outside of thevehicle (to the left as viewed in FIG. 12).

When the second link arms 52 pivot toward the outside of the vehicle andthus the first link arms 51 pivot likewise via the connecting arms 56,the extending arms 57 are extended toward the outside of the vehiclealong a specified path. When the extending arms 57 are thus extended,the seat body 2 moves from the seated position inside the vehicle to alower outside position (from a position shown by a solid line to aposition shown by a broken line in FIG. 12). When the motor 61 thenrotates in a reverse direction, the extending arms 57 move backwardalong the above-mentioned specified path, so that the seat body 2 ismoved from the lower outside position back to the seated position insidethe vehicle.

A rotation lock mechanism 70 for locking the movement of a rotatingsupport base 10, which will be described below, is provided on thebottom 53 b of the base 53 of the lift-up mechanism 50. Further, acircular-arc pinion gear 6 and a slide lock automatic release plate 7,which will be described below, are mounted to the underside of thebottom 53 b. The pinion gear 6 engages a rack 38 through an intermediategear 36 which will be described below, thereby providing a function ofcoupling the rotational movement with the longitudinal movement of theseat body 2. The slide lock automatic release plate 7 has a function ofautomatically releasing a slide lock mechanism 80, which will bedescribed below.

The rotating support base 10 will now be explained. As shown in FIG. 4,two parallel moving retaining members 11 and bases 12 form the rotatingsupport base 10. The retaining members 11 are spaced apart from eachother by a given distance and each of the bases 12 is mounted on andextends between the retaining members 11. A rotary disc 13 is mounted onthe topside of the bases 12. The rotary disc 13 has an outer ring 13 aand an inner ring 13 b, and a plurality of steel balls (not shown) areprovided between the outer and inner rings 13 a,13 b so as to permiteach of the rings 13 a,13 b to rotate smoothly with respect to the otherwithout rattling. The outer ring 13 a is secured to the topside of thebases 12, and the inner ring 13 b is secured to the underside of thebottom 53 b of the lift-up mechanism 50. With this arrangement, thelift-up mechanism 50 and thus the seat body 2 are rotatably supported onthe topside of the rotating support base 10. As clearly seen from FIG.6, the rotary disc 13 is mounted in a position corresponding to theexterior side end of the seat cushion 2 a of the seat body 2. Therefore,when the seat body 2 is rotated by about 90° toward the outside of thevehicle, a hip point HP on the seat cushion 2 a moves forward of thecenter of rotation (the rotary disc 13).

As shown in FIG. 4, two lock plates 71,72 are mounted on the back of therotating support base 10 and near the right side edge (the interior sideedge) on the base 10, respectively. The lock plates 71,72 serve toengage and disengage a lock pin 74 c of a rotation lock member 74mounted on the lift-up mechanism 50. The lock plates 71,72 are formedwith lock recesses 71 a,72 a for receiving the lock pin 74 c,respectively. As shown in FIG. 7, the rotation lock mechanism 70 on thelift-up mechanism 50 includes a lock release lever 73 and a rotationlock member 74. The lock release lever 73 is mounted on the underside ofthe left extending arm 57 on the front end thereof via a bracket 73 b topermit vertical pivotal movement. The lock release lever 73 is biased ina direction to move the front end of the lever 73 upwardly by a tensionspring (or alternatively a torsion spring) which is not shown.

A rear end (lower end) 73 a of the rotation lock release lever 73contacts one end of an intermediate member 75 that is mounted on thebase 53 of the lift-up mechanism 50 near the front left corner thereof.The intermediate member 75 is supported by a shaft 75 a for horizontalpivotal movement. Therefore, when the rotation lock release lever 73 isdepressed against the biasing force, the rear end 73 a is displacedrearward so as to push the one end of the intermediate member 75, thusrotating the intermediate member 75 counterclockwise.

One end of an operating wire 77 is connected to the other end of theintermediate member 75 and extends through the interior of a protectivetube 78 to near the rear left corner of the base 53. The rotation lockmember 74 is mounted on the rear left corner portion of the base 53 viaa bracket 79 to permit horizontal rotation around a shaft 74 a. The lockpin 74 c is mounted on the rotation lock member 74 and located more tothe interior side with respect to the shaft 74 a. An engaging portion 74d is provided on the end of the exterior side of the rotation lockmember 74. A tension spring 74 b is mounted between the end of theinterior side of the rotation lock member 74 and the bracket 79. Withthe tension spring 74 b, the rotation lock member 74 is biased in adirection to pull the lock pin 74 c, that is, in a direction (lockingdirection) to fit the lock pin 74 c into the lock recesses 71 a,72 a ofthe lock plates 71,72.

Further, the other end of the operating wire 77 is connected to theengaging portion 74 d. Therefore, when the intermediate member 75 ispushed by the rear end 73 a of the rotation lock release lever 73 andthus rotates, the operating wire 77 is pulled forward. Therefore, therotation lock member 74 is rotated in the unlocking direction(clockwise) against the biasing force of the tension spring 74 b.Consequently, the lock pin 74 c is disengaged from the lock recesses 71a,72 a of the lock plates 71,72, so that the rotation lock is released.When the rotation lock has been released, the lift-up mechanism 50 andthus the seat body 2 are permitted to rotate.

When the rotational operation of the rotation lock release lever 73 isreleased, the rotation lock member 74 is returned to the lockingdirection by means of the tension spring 74 b. Thus, the lock pin 74 cis returned to a position that permits engagement with the lock plates71,72. In this state, when the seat body 2 is rotated to the seatedposition or the sidewise position facing the door opening side, the lockpin 74 c is engaged with the lock recess 71 a (or 72 a ) of the rotationlock plate 71(or 72), thus locking the seat body 2 to prevent rotationin that position. Specifically, the lock member 74 is locked by the rearrotation lock plate 71 when the seat body 2 is rotated to the seatedposition facing the front of the vehicle, while the lock member 74 islocked by the interior side rotation lock plate 72 when the seat body 2is rotated to the sidewise position facing the door opening side.

As shown in FIG. 4, an auxiliary element 81 is mounted to the front base12 of the rotating support base 10 and protrudes forward from under thebase 12. The slide lock mechanism 80 is mounted on the protrudingportion of the auxiliary element 81. The slide lock mechanism 80 isshown in detail in FIG. 9. The auxiliary element 81 has an insertionhole 81 a into which a sleeve 82 is fitted. A cylindrical portion 83 aof a retainer 83 extends through the sleeve 82 for axial movement. Acompression spring 84 is disposed between a flange 83 b of the retainer83 and the auxiliary element 81. Thus, the retainer 83 is biased in adirection to move upward or in a direction to remove the cylindricalportion 83 a out of a lock hole 31 a.

A steel ball 85 is retained on the upper end of the retainer 83 so as topermit rotation and not to fall. The steel ball 85 is pressed againstthe slide lock automatic release plate 7 (FIG. 8) or the underside ofthe pinion gear 6 by the biasing force of the compression spring 84. Theslide lock automatic release plate 7 is mounted on the underside of thepinion gear 6. When the steel ball 85 is pressed against the slide lockautomatic release plate 7 as shown in a relative position (a) in FIG. 9,that is, when the seat body 2 is held in a position facing the front ofthe vehicle without being rotated, the retainer 83 is pressed downwardby the amount of thickness of the slide lock automatic release plate 7against the biasing force of the compression spring 84. Consequently,the lower end of the retainer 83 is inserted into the lock hole 31 athat is formed in a base 31 of the longitudinal support base 30 (FIG.4).When the cylindrical portion 83 a of the retainer 83 is inserted intothe lock hole 31 a, the rotating support base 10 and thus the seat body2 are locked to prevent longitudinal movement with respect to thelongitudinal support base 30.

On the other hand, when the seat body 2 is rotated to the door openingside, the pinion gear 6 and the slide lock automatic release plate 7 arerotated counterclockwise along an arc around the rotary disc 13. In thisprocess, when the steel ball 85 is disengaged from the slide lockautomatic release plate 7 as shown in relative positions (b) and (c) inthe drawing, the retainer 83 is moved upward by the amount of thicknessof the release plate 7 by the biasing force of the compression spring84. Consequently, the lower end of the retainer 83 is pulled out of thelock hole 31a. Thus, the lock of the seat body 2 to prevent thelongitudinal movement is automatically released. Although in FIG. 9, theslide lock mechanism 80 is shown located at a plurality of positionswith respect to the pinion gear 6 and the slide lock automatic releaseplate 7, it is to be noted that the pinion gear 6 and the slide lockautomatic release plate 7 actually move with respect to the slide lockmechanism 80 because the former are rotatable and the latter is fixed.

As shown in FIG. 10, a V-shaped groove 11 a is formed on the outer sidesurface of each of the two moving retaining members 11 of the rotatingsupport base 10. A pair of parallel fixed retaining members 32 aremounted on and extend along both sides of the base 31 of thelongitudinal support base 30 with a predetermined spacing therebetween.The fixed retaining members 32 are disposed along the outer side surfaceof the moving retaining members 11. A V-shaped groove 32 a, which issimilar to the groove 11 a, is also formed in each of the fixedretaining members 32 on the side surface facing the moving retainingmember 11. The groove 32 a is disposed facing the groove 11 a. Aplurality of steel balls 33 are fitted in the grooves 11 a,32 a betweenthe moving retaining members 11 and the fixed retaining members 32, tothereby form a pair of left and right linear guide mechanisms 34. Thelinear guide mechanisms 34 serve to permit the rotating support base 10and thus the lift-up mechanism 50 and the seat body 2 to move smoothlywithout rattling in the longitudinal direction of the vehicle. The steelballs 33 comprise rolling elements as described in the scope of demand.However, the rolling elements are not limited to the steel balls 33, butalso may be a cylindrical roller. Although not shown, the longitudinalsupport base 31 is secured to the vehicle floor by bolts, so that therotating seat 1 is installed on a specified position (passenger's seatposition) in the vehicle compartment.

Coupling means that serves to couple the rotational movement and thelongitudinal movement of the seat body 2 will now be described. As shownin FIGS. 4 and 8, a rack 38 is mounted on the side surface of the fixedretaining member 32 on the interior side. An intermediate gear 36 isrotatably mounted on the upper surface of the moving retaining member 11via a support plate 35. The intermediate gear 36 engages the rack 38.The position and length of the rack 38 are chosen such that thisengagement is maintained over the entire longitudinal moving range ofthe seat body 2.

As shown in FIGS. 6 and 8, the pinion gear 6 has a circular-arc shapeextending in a range of about 90° 0 and no engagement teeth are providedwithin a predetermined angular range α (about 26° in the firstembodiment) on the initial engagement side (the counterclockwise endside). Therefore, the pinion gear 6 does not engage the rack 38 withinthe initial range of about 26° at the beginning of rotation, in whichthe seat body 2 is rotated from the initial seated position (theposition facing the front of the vehicle, as shown by solid line in FIG.6) to the door opening side (in the counterclockwise direction). Thus,the seat body 2 only rotates without moving forward (in the“non-coupling range”).

When the seat body 2 is further rotated to the door opening side, thepinion gear 6 engages the intermediate gear 36. Thus, the intermediategear 36 rotates in synchronization with the rotational movement of theseat body 2. By being in engagement with the rack 38, the intermediategear 36 moves forward with respect to the vehicle while rotating. As aresult, the rotating support base 10 moves forward of the vehicle, andthus the seat body 2 rotates while moving forward (in the “couplingrange”).

The timing when the steel ball 85 is disengaged from the slide lockautomatic release plate 7 to release the slide lock (when it reaches tothe relative position (b) in FIG. 9) is chosen to be immediately beforethe pinion gear 6 engages the intermediate gear 36 by rotation of theseat body 2. Specifically, within the initial range of about 26° at thebeginning of rotation of the seat body 2 from the initial seatedposition to the door opening side, the steel ball 85 abuts against theslide lock automatic release plate 7 and the cylindrical portion 83 a ofthe retainer 83 is held inserted into the lock hole 31 a (in therelative position (a) in FIG. 9). Thus, the seat body 2 is held lockedto prevent movement in the longitudinal direction.

When the seat body 2 rotates by about 26°, the steel ball 85 isdisengaged from the slide lock automatic release plate 7 to release theslide lock (in the relative position (b) in FIG. 9). Then, the retainer83 is displaced upwardly by the biasing force of the compression spring84, and thus the cylindrical portion 83 a is moved out of the lock hole31 a (in the relative position (c) in FIG. 9). Consequently, the seatbody 2 is allowed to move longitudinally (i.e. “automatic release of theslide lock”). Thereafter, the steel ball 85 is held pressed against theunderside of the pinion gear 6 and thus the slide lock release state ismaintained until the seat body 2 reaches the sideways position facingthe door opening side.

On the other hand, before the seat body 2 has rotated by about 64° fromthe sideways position facing the door opening side toward the seatedposition, the retainer 83 of the slide lock mechanism 80 is helddisplaced upwardly, so that the slide lock is released. Thus, the seatbody 2 moves rearward while rotating toward the seated position(clockwise). When the seat body 2 rotates by about 64° from the sidewaysposition to the seated position, the seat body 2 returns to the rearmostposition in the longitudinal direction with respect to the vehicle. Atthe same time, the steel ball 85 is engaged with the slide lockautomatic release plate 7. As a result, the retainer 83 is depressedagainst the biasing force of the compression spring 84 and thecylindrical portion 83 a is inserted again into the lock hole 31 a.Thus, the seat body 2 is locked to prevent longitudinal movement in therearmost position (in the relative position (b) in FIG. 9). Thereafter,the seat body 2 only rotates about 26° to be returned to the seatedposition facing the front of the vehicle.

Thus, the automatic locking and unlocking of the slide lock mechanism 80is timed to the coupling of the rotation and the longitudinal movementof the seat body 2. The slide lock automatic release plate 7 isconfigured to have a proper dimension and shape and is mounted in such aposition that allows such locking and unlocking.

Covers 41,42,43 cover the left and right sides and the rear side so asto prevent foreign materials from entering through the sides to thusprevent malfunctioning and further to improve the appearance.

The most typical operation procedures for the rotating seat 1 thusconstructed will now be described with reference to FIGS. 11(A) to11(D). In these drawings, the rearmost position and the front positionin the longitudinal moving range of the seat body 2 are shown by L0 andL1, respectively, with reference to the center of the rotation of theseat body 2 (i.e. the center of the rotation of the rotary disc 13); andthe interior side position and the exterior side position in the lateralmoving range are shown by W0 and W1, respectively.

FIG. 11(A) shows the seat body 2 in the seated position. An operatordepresses the rotation lock release lever 73 to release the rotationlock mechanism 70 in this seated position, and then rotates the seatbody 2 to the door opening D (counterclockwise in FIG. 11). FIG. 11(B)shows the seat body 2 thus rotated about 26°. During this period, thepinion gear 6 and the rack 38 do not engage with each other, so that theseat body 2 only rotates. At this stage, the seat body 2 is brought to aposition just before the seat cushion 2 a of the seat body 2 interfereswith the rear portion of the door opening D or a rear pillar P.Therefore, if the seat body 2 is further rotated as it is, the seat body2 will interfere with the pillar P so that the seat body 2 cannot berotated to the sideways position facing the door opening D.

When the seat body 2 is rotated by about 26°, however, the slide lockrelease plate 7 is disengaged from the steel ball 85 of the slide lockmechanism 80 to thus allow the retainer 83 to move upwardly. Thus, thecylindrical portion 83 a is moved out of the lock hole 31 a, so that theseat body 2 is allowed to move forward (i.e. “automatic release of theslide lock”). At the same time, the pinion gear 6 and the intermediategear 36 start to engage with each other.

Therefore, when the seat body 2 is further rotated thereafter, couplingwith this rotational movement, the seat body 2 moves forward byengagement between the pinion gear 6 and the intermediate gear 36 and byengagement between the intermediate gear 36 and the rack 38. The seatbody 2 thus moves forward while rotating the remaining about 64°. As aresult, as shown in FIG. 11(C), the seat body 2 turns to the sidewaysposition facing the door opening D and moves to the front position L1.Because the seat body 2 is thus moved forward while rotating, theoccupant's foot or the footrest is prevented from interfering with thefront end of the door opening D. In this respect, if the seat body isrotated after being moved to the front position like the prior art, theoccupant's foot will interfere with the door opening (vehicle body).Such a problem can be eliminated by moving the seat body forward whilerotating, as in the first embodiment.

When the seat body 2 turns to the sideways position, the lock pin 74 cis locked by the rotation lock plate 72 on the interior side of therotating support base 10, so that the seat body 2 is locked to preventrotation in the sideways position. The seat body 2 is also locked toprevent longitudinal movement by being locked to prevent rotation. Withengagement between the pinion gear 6 and the intermediate gear 36 andengagement between the intermediate gear 36 and the rack 38, therotational movement and the longitudinal movement of the seat body 2 arecoupled to each other.

Next, the electric motor 61 on the lift-up mechanism 50 is rotated inthe normal direction to extend the extending arms 57 to the exteriorside so as to move the seat body 2 from the interior side position W0shown in FIG. 11(C) to the exterior side position W1 shown in FIG.11(D). In this process, the seat body 2 is lowered down to a specifiedlevel while moving to the exterior side position W1. After the seat body2 has been lowered down to the specified level outside, the electricmotor 61 and thus the lift-up mechanism 50 are stopped. In this state,the occupant may leave the seat. Thus, the seat body 2 is graduallydisplaced to a lower level (for example, to the same level as awheelchair) while moving to the exterior of the vehicle through the dooropening D. If the occupant wishes to move directly from the exteriorside position W1 to the wheelchair, the occupant can easily move fromthe seat body 2 to the wheelchair. Further, in the first embodiment, inwhich the seat body 2 is moved laterally with respect to the vehicle byusing the quadric link mechanism, the seat body 2 can be lowered andraised by a larger amount even in less lateral space, compared with aconstruction that moves by means of a slide mechanism. Therefore, theseat body 2 can be moved to a sufficiently lower level even in a vanhaving a compartment floor at a relatively high level.

Further, as shown in FIG. 11(D), in the process in which the seat body 2is moved to the exterior of the vehicle by operation of the lift-upmechanism 50, even if wind pushes against the opened door Dr in adirection that would close the door, the door is held in the openedposition by the seat cushion 2 a of the seat body 2. Therefore, the doordoes not interfere with the occupant's entry/exit.

In order to return the seat body 2, which has thus been moved to theexterior side position W1, to the original seated position, the electricmotor 61 is rotated in the reverse direction to move the lift-upmechanism 50 in the backward direction. Thus, the seat body 2 isreturned to the interior side position W0 shown in FIG. 11 (C), whilebeing raised. When the seat body 2 has been returned to the interiorside position W0, the electric motor 61 and thus the lift-up mechanism50 are stopped. Thereafter, the rotation lock mechanism 70 is releasedand the seat body 2 is manually rotated to the interior side. In thisstage, the engagement between the pinion gear 6 and the intermediategear 36 and the engagement between the intermediate gear 36 and the rack38 are maintained, and the seat body 2 moves from the front position L1to the rearmost position L0 while rotating to the interior side.

When the seat body 2 is rotated by about 64° from the sideways positionto the interior side, the seat body 2 is returned to the rearmostposition L0 shown in FIG. 11(B). Thereafter, the seat body 2 is furtherrotated by about 26° to be returned to the seated position shown in FIG.11(A). In this rotational range of about 26°, the pinion gear 6 isdisengaged from the intermediate gear 36 and the slide lock releaseplate 7 is moved onto the steel ball 85 of the slide lock mechanism 80.As a result, the slide lock mechanism 80 is returned to the lockedstate, so that the seat body 2 only rotates without moving in thelongitudinal direction.

With the rotating vehicle seat 1 having the above construction accordingto the first embodiment, the seat body 2 is supported by the lift-upmechanism 50, the rotating support base 10 and the longitudinal supportbase 30. The pinion gear 6 and the rack 38 that engage with each othervia the intermediate gear 36, are disposed between the lift-up mechanism50 and the longitudinal support base 30. Therefore, the rotationalmovement and the longitudinal movement of the seat body 2 are coupled toeach other. Thus, for example, even in the case of a sedan type carhaving a narrow door opening D, the seat body 2 can be turned to thedoor opening D without interfering with a pillar or other portions ofthe car and without the occupant's foot interfering with the edge of thedoor opening D. Therefore, usability can be greatly improved.

Further, because the rotary disc 13 is mounted on the exterior side endunder the seat cushion, a larger space can be provided under theinterior side of the seat cushion. Therefore, the pinion gear 6 that ismounted may be of a large diameter. With the larger diameter pinion gear6, the longitudinal moving distance of the seat body 2 can be increased.Therefore, the rotating seat 1 can be suitably utilized, especially in avan that requires a relatively long longitudinal moving distance for theseat body. Furthermore, because the center of rotation of the seat body2 is positioned closer to the exterior side than the hip point HP, theseat body can be moved forward with respect to the vehicle simply byrotating the seat body 2 to the exterior side. Also in this respect, alonger longitudinal moving distance of the seat body 2 can be provided.

Further, in this embodiment, the linear guide mechanism 34 that consistsof the moving retaining member 11, the fixed retaining member 32 and theplurality of steel balls 33 fitted into the grooves 11 a,32 a of theretaining members 11,32, is used as a linear guide mechanism for movingthe seat body 2 longitudinally with respect to the seat body. With thismechanism, the seat body 2 can be moved smoothly without rattling in thelongitudinal direction of the vehicle. In this respect, if a linearguide mechanism that consists of a rail having a U-shaped cross sectionand a roller inserted for rolling movement into the interior of the railis used, a proper clearance is required between the roller and the railin order to move the seat body smoothly. Such a clearance, however,causes the seat body to rattle. The linear guide mechanism 34 of thisembodiment can eliminate such a problem and can provide a rotating seat1 having excellent supporting rigidity (without rattling).

Further, because the quadric link mechanism is used as a mechanism formoving the seat body 2 laterally with respect to the vehicle, the seatbody 2 can be lowered and raised between a higher seat position and alower outside position near the ground even in a limited space, or in ashort moving distance, in the lateral direction of the vehicle. On theother hand, if a mechanism that is constructed to permit the seat body 2to simply slide along a rail that is inclined in the lateral directionof the vehicle is used, a wider space is required in the lateraldirection of the vehicle, even for the same vertical moving distance.Therefore, the lift-up mechanism 50 that essentially consists of thequadric link mechanism, permits the seat body 2 to be lowered and raisedby a large amount between the vehicle floor and the ground, withoutrequiring a large space in the lateral direction of the vehicle even ina car having a relatively great height, such as a van, as in the firstembodiment.

Various changes or modifications may be added to the above-describedfirst embodiment. For example, in the above embodiment, while only thelift-up mechanism 50 is electrically driven, the rotating support base10 and the longitudinal support base 30 may also be electrically driven.Alternatively and to the contrary, the lift-up mechanism 50 may bemanually operated like the rotating support base 10 and the longitudinalsupport base 30.

Further, if the seat body 2 is not required to move to the outside ofthe vehicle, the quadric link mechanism of the lift-up mechanism 50 andthe actuator 60 may be omitted.

Further, although the first embodiment has been described with respectto a rotating seat for a passenger's seat, the rotating seat accordingto this invention is applicable to other seat positions, such as a rearseat and a driver's seat.

As disclosed, for example, in Japanese Laid-Open Patent Publication No.9-48271, a swing-down type lift-up mechanism using a quadric linkmechanism has been provided as a lift-up mechanism for a rotatingvehicle seat. Such a swing-down type lift-up mechanism uses an actuatorthat is formed by combination of a motor and a ball screw. As shown inFIG. 13, in the prior art, the actuator 60 is assembled such that, withthe threaded shaft 63 a of the ball screw being oriented to the rear ofthe seat, the nut 63 b of the ball screw is connected to the link arm 59of the link mechanism. The threaded shaft case for rotatably supportingthe threaded shaft is connected to the vehicle floor. With this priorart construction, when the electric motor of the actuator 60 is started,the threaded shaft 63 a rotates and the nut 63 b moves along thethreaded shaft 63 a. The link arms 51,52 swing with the movement of thenut 63 b to thereby move the seat body 2 to the outside of the vehicleor back to the seated position in the inside of the vehicle.

However, if the rotating vehicle seat having the above-described priorart swing-down type lift-up mechanism is used, because the actuator 60is assembled with the threaded shaft 63 a being oriented to the rear ofthe seat (to the right as viewed in the drawing), the threaded shaft 63a protrudes close to the feet of the occupant sitting in a seat behindthe rotating seat. Therefore, the protruding threaded shaft may contactand soil the clothes of the occupant in the back seat, which maydistress or offend the back seat occupant. The invention as described inclaim 8 is provided to solve this problem.

In the rotating vehicle seat 1 according to the first embodiment thathas been described above, the actuator 60 is assembled in the quadriclink type lift-up mechanism 50 in an orientation to locate the threadedshaft 63 a at the front of the seat body 2 and to locate the gear box 62at the back of the seat body 2. Thus, unlike the prior art, the threadedshaft 63 a does not protrude toward a person sitting in a seat behindthe rotating seat. Therefore, the occupant in the back seat does notneed to be worried that his or her clothes may be soiled by the threadedshaft or be offended by the soiled clothes.

Further, the actuator 60 moves rearward of the seat body 2 only when theseat body 2 is moved to a lower position outside the vehicle.Specifically, the actuator 60 is located back to the forward positionwhen the seat body 2 is in the seated position in the inside of thevehicle, such as when the vehicle is running. Therefore, the actuator 60is kept out of the back seat occupant's way.

Further, with this quadric link type lift-up mechanism 50, the seat body2 can be lowered and raised between a higher seat position and a loweroutside position near the ground even in a limited space, or in a shortmoving distance, in the lateral direction of the vehicle. On the otherhand, if a mechanism that is constructed to permit the seat body 2 tosimply slide along a rail that is inclined in the lateral direction ofthe vehicle is used, a wider space is required in the lateral directionof the vehicle, even for the same vertical moving distance. Therefore,the lift-up mechanism 50 that essentially consists of the quadric linkmechanism, permits the seat body 2 to be greatly lowered and raisedbetween the vehicle floor and the ground, without requiring a largespace in the lateral direction of the vehicle even in a car having arelatively great height, such as a van, as in the first embodiment.

An embodiment of the present invention as defined in claim 2 (a secondembodiment) will now be described.

Although the rotating vehicle seat 1 of the first embodiment has aquadric link type lift-up mechanism 50 provided to move the seat body 2laterally with respect to the vehicle, rotating vehicle seats thatinclude a slide-type lateral moving means using a linear slide mechanisminstead of the quadric link type lift-up mechanism 50 are provided. Arotating vehicle seat 100 of this type is shown in FIGS. 19 and 20. Theseat body 2 is rotatably supported by the rotary disc 13 on a rotatingsupport base 110 via the seat base 5 mounted on the underside of theseat body 2. The rotating support base 110 is supported by alongitudinal support base 130 to permit movement in the longitudinaldirection of the vehicle (in a direction perpendicular to the plane ofthe drawing as viewed in FIG. 19; in the lateral direction as viewed inFIG. 20). In FIG. 20, the seat body 2 is not shown, and only the seatbase 5 is shown.

A coupling mechanism, which is similar to that of the first embodiment,is also incorporated in this slide-type rotating vehicle seat 100.Specifically, a rack is mounted on the longitudinal support base 130, anintermediate gear that engages the rack is mounted on the rotatingsupport base 110, and a pinion gear that engages the intermediate gearis mounted on the seat body 2. Thus, by coupling with the rotationalmovement of the seat body 2, the seat body 2 moves longitudinally withrespect to the vehicle.

The longitudinal support base 130 is supported by a slide-type lateralsupport base 150 to permit movement in the lateral direction of thevehicle (in the lateral direction as viewed in FIG. 19; in the verticaldirection as viewed in FIG. 20).

For a rotating seat in which the seat body 2 moves laterally withrespect to the vehicle by using the slide-type lateral support base 150,the seat body 2 needs to be restricted in its longitudinal movement androtational movement during its lateral movement. Therefore, in order toreliably restrict the seat body 2 in its longitudinal movement androtational movement during its lateral movement and also to reliablyrestrict the seat body 2 in its lateral movement in its seated position,the rotating vehicle seat 100 has been provided with a stopper 157 thatis mounted via a base 158 on the upper surface of a slide rail 151 onthe rear side of the lateral support base 150. As shown in the drawing,the stopper 147 is about half the length of the slide rail 151 and ismounted on and along the. slide rail 151 so as to extend from about themiddle to substantially the exterior side end of the slide rail 151. Asshown in FIG. 20, the front side edge (the left side edge as viewed inthe drawing) of the stopper 157 protrudes from the front side edge ofthe slide rail 151 by a predetermined amount and comprises a firststopper portion 157 a . Further, as shown in FIG. 19, the interior sideend of the stopper 157 is upwardly bent to be generally L-shaped andcomprises a second stopper portion 157 b.

When the seat body 2 is in the seated position, as shown in FIG. 20, therotating support base 10 is in the rearmost position and the seat body 2is in the seated position facing the front of the vehicle. In the seatedposition, the seat body 2 is locked to prevent rotation by means of therotation lock mechanism 70, which was described in the first embodiment.

With the seat body 2 in the seated position, the second stopper portion157 b of the stopper 157 is positioned adjacent to the exterior side ofthe interior side slide rail 112 a. The position of the second stopperportion 157 b or the length of the stopper 157 is determined so as torealize this condition. Therefore, the second stopper portion 157 bstops the rotating support base 10 and thus the seat body 2 from movingtoward the exterior side. Because the lateral movement of the seat body2 in the seated position is thus stopped by the second stopper portion157 b of the stopper 157, the lateral position of the seat body 2 in theseated position can be reliably locked.

When the rotation lock mechanism 70 is released and the seat body 2 isrotated to the exterior side, the seat body 2 moves forward whilerotating by the action of the coupling mechanism. When the seat body 2is rotated to the sideways position and moved to the front position inthe longitudinal sliding range, the rear end of the interior side sliderail 112 a of the rotating support base 110 moves forward (to the leftas viewed in FIG. 20) of the second stopper portion 157 b of the stopper157 and moves by a slight distance h forward of the first stopperportion 157 a of the stopper 157. Thus, lateral movement of the rotatingsupport base 110 is allowed. At this time, the seat body 2 is locked inthe sideways position to prevent rotation.

In this state, the seat body 2 can be moved to the exterior side bymeans of a linear driving mechanism which is not shown. In this processof moving the seat body 2 to the exterior side, a small clearance h ismaintained between the rear end of the interior side slide rail 112 a ofthe rotating support base 110 and the first stopper portion 157 a of thestopper 157. Thus, the longitudinal support base 130 and thus the seatbody 2 are allowed to move to the exterior side. On the other hand, thelongitudinal support base 130 is stopped from moving rearward by thefirst stopper portion 157 a being positioned to the rear (to the rightas viewed in FIG. 20) of the slide rails 112 a. As a result, therearward movement of the seat body 2 is stopped and thus the rotationalmovement of the seat body 2 is also stopped.

While the seat body 2 in the sideways position is, as described above,locked to prevent rotation by means of the rotation lock mechanism 70,the rotation lock mechanism 70 can be released at any time, irrespectiveof the position of the seat body 2. Therefore, if the rotation lockmechanism 70 is inadvertently released, the seat body 2 can rotate andcan also move rearward by being coupled to the rotational movement. Ifthe seat body 2 rotates or moves rearward while moving to the exteriorside, the seat body 2 and the occupant will interfere with the pillar atthe door opening, so that the seat body 2 cannot move smoothly to theexterior side. In this respect, by providing the stopper 157, therearward movement and the rotational movement of the seat body 2 arestopped in the process of movement of the seat body 2 to the exteriorside. Therefore, even if the rotation lock mechanism 70 is inadvertentlyreleased, the seat body 2 can be moved straight to the exterior sidewithout interference of the seat body 2 and the occupant with the pillarat the door opening.

Further, in the process of moving the seat body 2 to the exterior side,as described above, the rear end of the slide rail 112 a passes alongthe side of the first stopper portion 157 a, so that the seat body 2 isstopped from moving rearward. Further, the seat body 2 moves to theexterior side with the lock member 74 of the rotation lock mechanism 70being held engaged with the lock plate 71. Therefore, the lock pin 74 cof the rotation lock member 74 that passes along the side of the firststopper portion 157 a, also causes the seat body 2 to be stopped frommoving rearward.

When the seat body 2 reaches the end position on the exterior side, therear end of the exterior side slide rail 112 a of the rotating supportbase 110 is disengaged from the side of the first stopper portion 157 a.However, the lock pin 74 b is still positioned to the side of the firststopper portion 157 a, so that the seat body 2 is stopped from movingrearward and rotating in the end position as well.

The above-described stopper 157 can work properly when the pair of leftand right slide rails 112 a,112 b of the longitudinal support base 130are disposed on a horizontal plane and the slide rail 151 of the lateralsupport base 150 is disposed in an inclined position, as shown in FIG.19. If the slide rail 151 is not disposed in an inclined position, butrather in a horizontal position, when the seat body 2 is moved into theinside of the vehicle, the slide rail 112 a is disengaged from thestopper 157; however, the slide rail 112 b abuts against the stopper 157to thereby stop the rearward movement of the seat body 2, so that thestopper 157 cannot work. In light of this problem, in the constructionin which the slide rail 151 is disposed in a horizontal position, anotch may be provided on the stopper 157 in order that, when the seatbody 2 is in an interior retracted position, the slide rail 112 a of thelongitudinal support base 130 is located in a position to be allowed topass to the interior side of the second stopper portion 157 b of thestopper 157 and the seat body 2 can be allowed to move longitudinally atthe position of the slide rails 112 b. With this construction, however,during lateral movement of the longitudinal support base 130, the sliderail 112 b is disengaged from the stopper 157 to the outside and theslide rail 112 a enters the notch. In this state, the longitudinalmovement cannot be stopped.

The invention as described in claim 2 has been made to solve theabove-mentioned problems. It is, accordingly, an object of the inventionto provide a rotating vehicle seat in which, whether the lateral supportbase is disposed in a horizontal position or in an inclined position,the seat body can be moved longitudinally with respect to the vehiclewhen the longitudinal support base is in the inside of the vehicle, andwhich further includes a restricting arrangement that serves to restrictthe longitudinal movement of the seat body when the longitudinal supportbase is moving longitudinally along the lateral support base.

A rotating vehicle seat 190 of the second embodiment has a retainingmechanism 141 provided on the rear side (interior side) of thelongitudinal support base 130. In the following description, componentsthat do not require modifications to the first embodiment will beidentified by the same numerals.

The lateral support base 150 has a pair of slide rails 151 having aU-shaped cross-section. The slide rails 151 support vertical rollers 134and lateral rollers 135 of the longitudinal support base 130, which areshown in FIG. 14, to permit rolling movement. The slide rails 151 aredisposed parallel to each other at a predetermined spacing in thelateral direction of the vehicle. As shown in FIG. 17, the slide rails151 are supported horizontally on the vehicle floor F by an exteriorside pedestal 152 and an interior side pedestal 153 that have the samevertical length.

As shown in FIG. 14, the longitudinal support base 130 has a pair ofmain frames 131 and a pair of support frames 132. The main frames 131are disposed in the predetermined spacing provided between the sliderails 151 of the lateral support base 150. One of the support frames 132extends across the interior side ends of the main frames 131 and theother extends across the exterior side ends of the main frames 131. Abase 133 is mounted in a predetermined range on the exterior side of theframe formed by the main frames 131 and the support frames 132. A bentedge 133 a is formed on the exterior and interior side ends of the base133. An upright portion 131 a is formed on the interior side of each ofthe main frames 131.

Two vertical rollers 136 and two horizontal rollers 137 are rotatablymounted on the interior surface of each of the bent edges 133 a of thebase 133. The vertical rollers 136 and the horizontal rollers 137support the slide rails 112 of the rotating support base 110 (see FIG.19). Further, three vertical rollers 134 and two horizontal rollers 135are rotatably attached to the sides of the each main frame 131. Thevertical rollers 134 and the horizontal rollers 135 are inserted forrolling movement into the interior of the slide rails 151 of the lateralsupport base 150.

The restricting arrangement 141 is provided on one of the uprightportions 131 a that is formed on the interior side of the main frame 131on the rear side (the right side as viewed in the drawing) of thelongitudinal support base 130. The restricting arrangement 141 serves torestrict the rearward movement of the rotating support base 110 duringthe movement of the longitudinal support base 130 to the outside. Therestricting arrangement 141 is shown in detail in FIG. 16. Therestricting arrangement 141 includes a guide plate 142, a stopper member145 and a coil spring 147. A pair of guide pins 143 are mounted with apredetermined spacing therebetween on the upright portion 131 a of themain frame 131. The guide plate 142 is connected to the upright portion131 a via the guide pins 143 such that the guide plate 142 is disposedin a position generally opposed to and with a predetermined spacing fromthe upright portion 131 a. The guide plate 142 has a generallyrectangular plate-like shape, and a projection 142 b extends from apredetermined location of an upper edge 142 a of the guide plate 142. Ahole 142 c for receiving an end of the coil spring 147 is formed throughthe projection 142 b.

As shown in FIG. 15, the stopper member 145 is slidably mounted betweenthe guide plate 142 and the upright portion 131 a. As shown in FIG. 16,the stopper member 145 has a generally rectangular shape, which islonger in length than the guide plate 142. A recess 145 b is formed onthe stopper member 145 near an outer end 145 a on the exterior side andserves to permit the interior side slide rail 112 a of the rotatingsupport base 110 to move. A stopper portion 145 c is formed on the outerend 145 a. Further, a projection 145 d extends from the stopper member145 so as to be continuous with the recess 145 b and to have a heightcorresponding to the projection 142 b of the guide plate 142. A hole 145e for receiving the other end of the coil spring 147 is formed throughthe projection 145 d. The stopper member 145 also has a pair of slideslots 146 of a predetermined length for receiving the guide pins 143.

The stopper member 145 thus constructed is slidably supported betweenthe upright portion 131 a of the main frame 131 and the guide plate 142via the slide slots 146 by the guide pins 143. Further, the stoppermember 145 is biased toward the interior side by the coil spring 147connected between the projections 142 b,145 d through the receivingholes 142 c,145 e.

The operation of the restricting arrangement 141 will now be describedwith the movement of the seat body 2 with reference to FIGS. 11(A) to11(D) which have been described in the first embodiment. When the seatbody 2 is in the seated position (FIG.11(A)), as shown in FIG. 16, thestopper member 145 of the restricting arrangement 141 that is mounted onthe main frame 131 of the longitudinal support base, is in contact witha bent portion 159 a of an end plate 159 that is mounted on the end ofeach of the slide rails 151 of the lateral support base 150.Specifically, the stopper member 145 has been moved to the exterior sidevia the slide slots 146 against the spring force of the coil spring 147,and an interior side end 146 a of the slide slot 146 is in contact withthe guide pin 143.

In this state, the recess 145 b of the stopper member 145 is located ina position to permit the interior side slide rail 112 a of the rotatingsupport base 110 to move longitudinally. When the sliding rails 112 a,112 b have been moved rearward, the seat body 2 is in a seated position.

When the seat body 2 is in the seated position, the rotation lockmechanism 70 is released to rotate the seat body 2 to the side of thedoor opening D (counterclockwise in FIG. 11) (FIG.11(B)). Within apredetermined angular range at the beginning of rotation, the piniongear and the rack of the coupling mechanism do not engage with eachother, so that the seat body 2 only rotates without moving forward. Whenthe seat body 2 has been rotated to the exterior side by thepredetermined angle, the slide lock mechanism 80 is unlocked, so thatthe seat body 2 can move forward and at the same time, the pinion gearand the rack start to engage with each other. Therefore, when the seatbody 2 is further rotated thereafter, coupling with this rotationalmovement, the seat body 2 moves forward by engagement between the piniongear and the rack. The seat body 2 thus moves forward while rotating. Asa result, the seat body 2 turns to the sideways position facing the sideof the door opening D and moves to the front position L1 (FIG. 11(C)).

When the seat body 2 turns to the sideways position, the rear end of theinterior side slide rail 112 a of the rotating support base 110 isdisengaged from the recess 145 b of the stopper member 145 and is movedslightly forward of the stopper member 145. Then, the lock member 74 islocked by the rotation lock plate 72 on the rear right side of therotating support base 110, so that the seat body 2 is locked to preventrotation in the sideways position.

Next, when the seat body 2 is moved from the interior side position W0shown in FIG. 11(C) to the exterior side position W1 shown in FIG.11(D), the restricting arrangement 141 mounted on the main frame 131 ofthe longitudinal support base 130 also moves together with the seat body2. As a result, the stopper member 145, which has abutted against theend plate 159 mounted on the slide rail 151 of the lateral support base150 and has thus been moved to the exterior side against the springforce of the coil spring 147, is moved to the interior side by therestoring force of the coil spring 147, as shown in FIG. 16 by a brokenline. At the same time, the stopper portion 145 c moves toward the endof the slide rail 112 a. When an end 146 b of the slide slot 146contacts the guide pin 143, the stopper portion 145 c is positionedfacing the end of the slide rail 112 a, so that longitudinal movement ofthe slide rails 112 a and thus longitudinal movement of the seat body 2are stopped. In this state, the seat body 2 is moved to the positionshown in FIG. 11(D), in which the occupant may leave the seat.

In order to return the seat body 2, which has thus been moved to theexterior side position W1, to the original seated position, the linearslide mechanism of the lateral support base 150 is actuated in thereverse direction to return the seat body 2 to the interior sideposition W0 shown in FIG. 11(C). When the seat body 2 comes to aposition slightly before the interior side position W0, the interiorside end of the stopper member 145 of the restricting arrangement 141mounted on the main frame 131 of the longitudinal support base 130,starts to contact the end plate 159 of the lateral support base 150.Thus, the stopper member 145 moves to the exterior side against thespring force of the coil spring 147. When the end 146 a of the slideslot 146 contacts the guide pin 143, the stopper portion 145 c islocated to the exterior side of the position in which the stopperportion 145 c faces the slide rail 112 a, and the recess 145 b islocated in a position to permit the slide rail 112 a to movelongitudinally. In this state, the rotation lock mechanism 70 isreleased and the seat body 2 is manually rotated to the interior side.In this stage, the pinion gear and the rack of the coupling mechanismare held in engagement with each other, and the seat body 2 moves fromthe front position L1 to the rearmost position L0 while rotating to theinterior side.

When the seat body 2 is rotated by a predetermined angle from thesideways position to the interior side, the seat body 2 is returned tothe rearmost position L0 shown in FIG. 11(B). Thereafter, the seat body2 is further rotated to be returned to the seated position shown in FIG.11(A). In the latter half of the rotational range, the pinion gear isdisengaged from the rack and the slide lock release plate 7 is alsodisengaged from the roller 82. As a result, the slide lock mechanism 80is returned to the locked state, so that the seat body 2 only rotateswithout moving in the longitudinal direction.

As described above, the rotating vehicle seat 190 of the secondembodiment includes the rotating support base 110 for rotatablysupporting the seat body 2, the longitudinal support base 130 forsupporting the rotating support base 110 to permit movement in thelongitudinal direction of the vehicle, the lateral support base 150 forhorizontally moving the seat body 2 in the lateral direction of thevehicle, and the coupling mechanism for coupling the rotational movementand the longitudinal movement of the seat body 2. In this rotating seat190, the restricting arrangement 141 is mounted on the lateral supportbase 150 in a manner that permits lateral movement with the longitudinalsupport base 130, and serves to restrict the longitudinal movement ofthe longitudinal support base 130 at a position other than a particularposition (seated position) within the lateral moving range of thelongitudinal support base 130.

Therefore, in the restricting arrangement 141 of the second embodiment,when the seat body 2 is in the seated position, the stopper member 145abuts against the end plate 159 of the lateral support base 150. Thus,the stopper member 145 moves to the exterior side and the recess 145 bis located in a position to permit the longitudinal movement of theslide rail 112 a. When the seat body 2 is rotated to the sidewaysposition facing the door opening side while sliding by the couplingmeans, the rear end of the slide rail 112 a is located more to the frontof the vehicle than the stopper member 145 with a slight spacingtherebetween. The longitudinal support base 130 horizontally moves tothe exterior side along the lateral support base 150 that is disposedhorizontally. As a result, the stopper portion 145 c of the stoppermember 145 moves by the restoring force of the coil spring 147 to aposition that faces the end of the slide rail 112 a. This state ismaintained over the range of horizontal movement of the seat body 2 tothe exterior side, so that the rearward movement of the slide rail 112 acan be restricted.

Further, because the restricting arrangement 141 is connected inparallel to the upright portion 131 a of the rear main frame 131, evenif, for example, the length of the slide rail 151 of the lateral supportbase 150 is changed, the relationship between the stopper member 145 ofthe restricting arrangement 141 and the slide rail 112 a is not changed,so that no change is required to the position of the restrictingarrangement 141. Unlike the stopper member 157 in the above-mentionedknown rotating seat, the stopper member 157 does not need to be changedto a longer one when the slide rail 151 is changed to a longer one.Thus, a reduction of the weight can be achieved. Further, therestricting arrangement 141 provides greater economies in that it canalso be applied to an existing device which is similar to the rotatingseat 190.

Although, in the second embodiment, the lateral support base 150 hasbeen described as being disposed horizontally, the lateral support base150 may be disposed in an inclined position, as in the known rotatingseat. In this case, preferably, as shown in FIG. 18, the stopper portion145 c of the stopper member 145 may be shaped to correspond to theposition of the slide rail 112 a.

Further, although the stopper member 145 has been described as beingconstructed to move into or out of the travelling path of the seat bodyby moving in the lateral direction of the vehicle, the stopper membermay be in the form of, for example, a solenoid actuator. In this case, asensor may be also provided to detect when the seat body reaches theinterior side end of the lateral support base. The solenoid actuator isoperated based on the output signal of the sensor, and the rod of theactuator protrudes into the longitudinal travelling path of the seatbody. Such a construction (electrical) may be applied to restrict thelongitudinal movement during the lateral movement of the seat body.

An embodiment of the invention as described in claim 3 or 5 (a thirdembodiment) will now be explained with reference to FIGS. 21 to 32, 83and 84. FIG. 21 shows the interior of the vehicle, with a driver's seat210 and a passenger's seat 211. In this embodiment, a rotating vehicleseat will be described as being applied to the passenger's seat 211. Adoor opening D is located on the left of the passenger's seat 211. Inthe drawings, the front of the vehicle is shown by a “forward” arrow,and the side having a door opening is shown by an “outside” arrow.

The passenger's seat in the form of the rotating vehicle seat 211according to this embodiment includes a seat body 212, a lateral supportbase 213 for supporting the seat body 212 to permit sliding movement inthe lateral direction of the vehicle, a rotating support base 214 forrotatably supporting the lateral support base 213 and a longitudinalsupport base 215 for supporting the rotating support base 214 to permitsliding movement in the longitudinal direction of the vehicle.

As shown in FIG. 23, the seat body 212 has a seat cushion 212 a and aseat back 212 b. A seat holder 216 having a footrest 216 a, as shown inFIG. 24, is mounted on the underside of the seat cushion 212 a. The seatbody 212 is mounted on the lateral support base 213 via the seat holder216.

As shown in FIG. 25, the lateral support base 213 has a pair of rightand left linear slide mechanisms 220. As shown in FIGS. 26 to 28, eachof the linear slide mechanisms 220 includes a fixed rail 220 a, a movingrail 220 b and a plurality of steel balls 220 c disposed betweenV-shaped grooves 220 d of the rails 220 a and 220 b.

As shown in FIG. 25, the moving rails 220 b are connected to each otherat the front ends and the rear ends by connecting bases 224 and 225,respectively, thus forming a frame on the sliding side (slide frame221). Brackets 226,227 are mounted across the moving rails 220 b in agenerally medial portion of the slide frame 221 and on and along thefront connecting base 224 a, respectively. The seat holder 216 ismounted on the brackets 226,227. Thus, the seat body 212 is mounted onthe slide frame 221 and thus the lateral support base 213.

A generally box-like connecting base 229 is mounted across the rear endsof the fixed rails 220 a. As a driving source for the lateral supportbase 213, a motor 230 is mounted to the connecting base 229. One end ofa threaded shaft 231 is connected to the motor 230 via a reduction geartrain 230 a. Further, the front ends of the fixed rails 220 a are alsoconnected to each other by a connecting base 228. The other end of thethreaded shaft 231 is rotatably supported by a bracket 228 a mounted onthe connecting base 228. Thus, the fixed rails 220 a are also formed inone piece by the connecting bases 228,229, thereby forming a slide fixedframe 222.

A nut 232 is secured to the connecting base 225 of the slide frame 221by the bracket 233 and is adapted to engage the threaded shaft 231. Whenthe motor 230 is started, the threaded shaft 231 rotates and thus thenut 232 moves on and along the threaded shaft 231. As a result, theslide frame 221 and thus the seat body 212 move in the lateral directionof the vehicle (in the sliding direction of the linear slide mechanism220).

The position of one of the fixed rails 220 a (on the front as viewed inFIG. 25) can be adjusted in a direction perpendicular to the slidingdirection (toward or away from the other fixed rail 220 a). When suchposition adjustment is made properly, the spacing between the fixedrails 220 a can be adjusted to thereby provide a proper pre-load on thelinear slide mechanisms 220. As a result, rattling in a directionperpendicular to the sliding direction (in the vertical direction and inthe horizontal direction) can be minimized. This position adjustingmechanism is shown in detail in FIGS. 26 to 28.

As shown in FIG. 27, an L-shaped bracket 240 is mounted in a generallymedial portion in the sliding direction of each of the fixed rails 220a. The bracket 240 is fixed on a rotating base 241. The lateral supportbase 213 is mounted on an inner ring 214 a of a rotating support base214, which will be described below, by the rotating base 241. The rightone (as viewed in FIG. 27) of the brackets 240 can adjust its positionin the lateral direction in the drawing, so that the spacing between themedial portions in the sliding direction of the fixed rails 220 a can beadjusted.

FIG. 26 shows the position adjusting mechanism at the rear of the fixedrails 220 a. A threaded hole 229 a is formed through a right side wall229 a (as viewed in the drawing) of the box-like connecting base 229,and an adjusting bolt 242 is threadably inserted through the threadedhole 229 b. The adjusting bolt 242 extends through the side wall 229 aand abuts against an outer surface of the fixed rail 220 a. Therefore,the spacing between the fixed rails 220 a can be changed by adjustingthe amount of insertion of the adjusting bolt 242. The amount ofinsertion of the adjusting bolt 242 can be fixed by tightening a nut243.

FIG. 28 shows a position adjusting mechanism at the front of the fixedrails 220 a. An auxiliary portion 234 is mounted on the front end of theconnecting base 228. A threaded hole 234 a is formed through theauxiliary portion 234. An insertion hole 220 aa is formed through thefront portion of the fixed rail 220 a, and an adjusting bolt 235 isinserted through the insertion hole 220 aa. The adjusting bolt 235 isalso threadably inserted through the threaded hole 234 a. Therefore, thespacing between the fixed rail 220 a and the auxiliary portion 234 canbe adjusted by adjusting the amount of insertion of the adjusting bolt235 through the threaded hole 234 a. Thus, the spacing between the fixedrails 220 a can be adjusted. The amount of insertion of the adjustingbolt 235 can be fixed by tightening a nut 236.

As described above, the position of one of the fixed rails 220 a can beadjusted in the direction perpendicular to the sliding direction, atthree positions on the front, middle and rear in the sliding direction.In this way, the force of pushing the steel balls 220 c in the linearslide mechanisms 220 can be adjusted so as to provide a proper pre-loadon the rear linear slide mechanisms 220. As a result, the seat body 212can slide smoothly in the lateral direction of the vehicle withoutrattling.

In this respect, a known linear slide mechanism is constructed, forexample, such that the rails 207 is formed by bending a band steel plateusing a stamping process into a generally U-shaped cross-section asshown in FIG. 31 and the rails 207 support rollers 208 to permit therollers 208 to move within the interior of the rails 207. In thisconstruction, it is difficult to correct rattling in the verticaldirection, because of the press bending inaccuracy of the rails 207, anda pre-load cannot be exerted.

Further, the above-mentioned known linear slide mechanism, as shown inFIG. 32 in which a resin piece 209 is pressed against the U-shapedrails, requires a means for minimizing horizontal rattling. The linearslide mechanisms 220 according to this embodiment, which is constructedby disposing the steel balls 220 c between the V-shaped grooves 220 d,can easily provide sliding movement without rattling in the vertical andhorizontal directions, and does not require such means in the knownlinear slide mechanism.

The rotating support base 214 and the longitudinal support base 215 areshown in detail in FIG. 29. The rotating support base 214 serves torotate the lateral support base 213 and the seat body 212 by about 90°between the position facing the front of the vehicle and the positionfacing the door opening side D. The longitudinal support base 215 servesto move the rotating support base 214, the lateral support base 213 andthe seat body 212 in the longitudinal direction of the vehicle.

The lateral support base 213 is mounted on the inner ring 214 a of therotating support base 214 by means of the brackets 240 and the rotatingbase 24, as described above. The rotating support base 214 alsoincorporates a slide mechanism of the same type as the above-mentionedlinear slide mechanism 220. Specifically, V-shaped grooves, which arenot shown, are formed in the outer peripheral surface of the inner ring214 a and in the inner peripheral surface of the outer ring 214 b,respectively. A plurality of steel balls are disposed between theV-shaped grooves. With the rotating support base 214 thus constructed,the seat body 212 can be rotated smoothly without rattling.

The rotating support base 214 is mounted on a main base 250 of thelongitudinal support base 215. The main base 250 is mounted on thevehicle floor F via a pair of right and left linear slide mechanisms 251to permit longitudinal movement. The linear slide mechanisms 251 areconstructed similarly to the above-mentioned linear slide mechanisms220. Specifically, each of the linear slide mechanisms 251 consists of afixed rail 251 a, a moving rail 251 b and a plurality of steel balls(not shown) disposed between V-shaped grooves 251 c that are formed inboth rails 251 a,251 b. Further, although it is not shown, one of thefixed rails 251 a incorporates a position adjusting mechanism similar tothat of the linear slide mechanism 220. Thus, an appropriate pre-load isexerted on the linear slide mechanisms 251, so that the main base 250can slide smoothly in the longitudinal direction of the vehicle withoutrattling.

A coupling mechanism 260 serves to couple the rotational movement andthe longitudinal sliding movement of the seat body 212. The couplingmechanism 260 consists of a circular-arc pinion gear 261 mounted to theunderside of the rotating base 241, an intermediate gear 262 mounted onthe main base 250 and a rack 263 mounted on the vehicle floor F. Thepinion gear 261 engages the intermediate gear 262, and the intermediategear 262 engages the rack 263. As shown in FIG. 30, the pinion gear 261does not have any engagement teeth within a predetermined range of anangle α (26° in this embodiment) on the forward portion thereof asviewed in the drawing. Therefore, the pinion gear 261 does not engagethe intermediate gear 262 within the range of the angle α. Thus, therotational movement of the seat body 212 is not coupled to thelongitudinal sliding movement of the seat body 212 (in the “non-couplingrange”). After the seat body 212 has been rotated by the angle α fromthe position facing the front of the vehicle to the side of the dooropening D, the pinion gear 261 starts to engage the intermediate gear262. Thereafter, by engaging the pinion gear 261 with the intermediategear 262 and the intermediate gear 262 with the rack 263, the rotationalmovement of the seat body 212 to the side of the door opening D iscoupled to the longitudinal sliding movement of the seat body 212.

On the other hand, when the seat body 212 is rotated from the side ofthe door opening D to a position facing the front of the vehicle, theseat body 212 slides rearward with respect to the vehicle (to the rightas viewed in FIG. 30) by being coupled with this rotational movement.Thus, a wider space can be provided close to the occupant's feet. Withthe coupling mechanism 260 thus constructed, the rotational movement andthe longitudinal sliding movement of the seat body 212 can be made in asingle operation, so that the usability of the vehicle rotating seat 211can be improved.

The rotating vehicle seat 211 having the above-described constructionaccording this embodiment, is held in a state shown in FIG. 21 while thevehicle is running. In this state, the seat body 212 is located in theposition facing the front of the vehicle within the moving range in therotational direction and the rear sliding end is within the moving rangein the longitudinal direction with respect to the vehicle. The lateralsupport base 213 is in a positional orientation in which itslongitudinal sides (along the linear slide mechanism 220) extend in thelongitudinal direction of the vehicle. On the other hand, when theoccupant of the rotating seat 211 tries to get into or out of thevehicle, the seat body 212 a is rotated to the door opening D. At thistime, the seat body 212 is first rotated by the angle at to the dooropening D, and thereafter, the seat body 212 slides forward with respectto the vehicle by coupling with the rotational movement. The seat body212 thus slides forward while rotating to the door opening side. Whenthe seat body 212 is rotated by about 90°, the seat body 212 moves tothe front position in the longitudinal direction of the vehicle. At thisstage, the rotational operation is stopped. The state in this stage isshown by a solid line in FIG. 22.

In the state shown by a solid line in FIG. 22, the seat body 212 is in aposition facing the door opening D within the moving range in therotational direction and the front sliding end is within the movingrange in the longitudinal direction with respect to the vehicle. Thelateral support base 213 is in a positional orientation in which itslongitudinal sides extend in the lateral direction of the vehicle. Inthis stage, the seat body 212 is in a rearmost position (the interiorside position, or the right end position as viewed in FIG. 22) withinthe moving range in the lateral direction with respect to the vehicle.In this state, when the driving motor 230 of the lateral support base213 is started, the threaded shaft 231 is rotated and thus the slidingframe 221 moves. As a result, the seat body 212 is moved to the outsideof the vehicle (to the position shown by a broken line in FIG. 22). Theseat body 212 can be returned to the inside of the vehicle by rotatingthe motor 230 in the reverse direction. The seat body 212 is first movedin the lateral direction back to the interior side position, and thenthe seat body 212 is rotated to the position facing the front of thevehicle. The seat body 212 also slides rearward with respect to thevehicle by coupling with the rotational movement. The lateral supportbase 213 also rotates together with the seat body 212 to be finallymoved back to a position in which its longitudinal sides extend in thelongitudinal direction of the vehicle.

In the rotating vehicle seat 211 thus constructed, the lateral supportbase 213 is rotated by the rotating support base 214 between theposition in which its longitudinal sides extend in the longitudinaldirection of the vehicle and the position in which its longitudinalsides extend in the lateral direction of the vehicle. When the vehicleis running (when the occupant is sitting in the seat), the lateralsupport base 213 is in a position in which its longitudinal sides extendin the longitudinal direction of the vehicle. Therefore, as shown inFIG. 21, the lateral support base 213 is not extended to the driver'sseat 210 when the vehicle is running. Thus, sufficient space S can beprovided between the driver's seat 210 and the passenger's seat 211 andcan be effectively utilized for various purposes such as a passage tothe rear seats.

Further, although the motor 230 is disposed on the rear portion of thelateral support base 213, the lateral support base 213 is located in aposition in which its longitudinal sides extend in the longitudinaldirection of the vehicle while the vehicle is running. Therefore, themotor 230 is located toward the rear seat and not toward the driver'sseat, while the vehicle is running. In this respect, too, a space S canbe sufficiently provided between the driver's seat 210 and thepassenger's seat 211.

Further, sufficient space S provided between the driver's seat 210 andthe passenger's seat 211 is also useful as a space for installing aparking brake lever, a console box or similar components.

Additionally, the position of one of the fixed rails 220 a of the linearslide mechanisms 220 in the lateral support base 213 can be adjusted ina direction perpendicular to the sliding direction. When such positionadjustment is performed properly, an appropriate pre-load can be exertedon the linear slide mechanisms 220. As a result, the seat body 212 canslide smoothly without rattling.

In this respect, as shown in FIGS. 83 and 84, a known rotating vehicleseat 291 includes a rotating support base 292 for rotatably supporting aseat body 295 between a position facing the front of the vehicle and aposition facing the door opening D, a longitudinal support base 293 forsupporting the rotating support base 292 to permit movement in thelongitudinal direction of the vehicle (in the vertical direction asviewed in FIG. 84), and a lateral support base 294 for supporting thelongitudinal support base 293 to permit sliding movement in the lateraldirection of the vehicle (in the lateral direction as viewed in FIGS. 83and 84). The lateral support base 294 is fixed in a position in whichits longitudinal sides extend in the lateral direction of the vehicle.Therefore, the lateral support base 294 requires a large space in thelateral direction of the vehicle.

Therefore, when the rotating vehicle seat 291 is used as a passenger'sseat, the space S between the passenger's seat 291 and the driver's seat296 is occupied by the lateral support base 294. Accordingly, space Scannot be utilized, for example, as a passage to rear seats R (whichpassage permits passengers to move between the passenger's seat 291 orthe driver's seat 296 and the rear seats R).

Further, although it is not shown, the lateral support base 294 has alinear driving mechanism as its driving source that essentially consistsof a motor and a ball screw. The motor of this linear driving mechanismis mounted in a manner to protrude from the rear sliding end (the rightend as viewed in the drawing) toward the driver's seat. In this respect,too, it is difficult to utilize space S effectively as a passage to therear seats R.

Additionally, space S provided between the driver's seat 296 and thepassenger's seat 291 may be utilized to install a parking brake lever ora stored box such as a console box, but with some limitations.

According to the invention as described in claim 3 (the thirdembodiment), the above-noted prior art problems can be eliminated.

Various modifications or changes may be added to the above-describedthird embodiment. For example, it has been described to have aconstruction in which positional adjustment in the lateral direction canbe made at three positions in the vicinities of the front end, middleand rear end in the sliding direction; but it also may be constructedsuch that the adjustment can be made at one or two positions, or fourpositions or more. Further, the description provides a construction suchthat the position of one of the fixed rails 220 a is adjusted; but italso may be constructed such that the positions of both fixed rails 220a are adjusted. Additionally, it also may be constructed such that theposition of the moving rail 220 b may be adjusted so as to provide anappropriate pre-load on the linear slide mechanisms 220.

An embodiment (a fourth embodiment) of the invention as described inclaim 4 will now be described with reference to FIGS. 33 to 40. FIGS. 33and 34 show a complete rotating vehicle seat 301 according to thisembodiment. In FIG. 33, a seat body 310 is shown separated from alift-up mechanism 350 so as to be used separately as a wheelchair. InFIG. 34, the seat body 310 is shown connected to a lateral support base360 to be moved into the inside of the vehicle.

The rotating vehicle seat 301 of this embodiment generally consists of aseat body 310 that can be used separately as a wheelchair and a lift-upmechanism 350 for moving and placing the seat body 310 in the inside ofthe vehicle by connecting the seat body 310.

The seat body 310 includes a seat cushion 311 and a seat back 312. Armrests 313 and a head rest 314 are provided on both sides of and on thetop of the seat back 312, respectively. Further, a handle 315 having abrake lever 316 is mounted on the back of the seat back 312 to beoperated by the passengers' helpers.

A connecting base 320 is mounted on the underside of the seat cushion311, and retractable wheel frames 321 are mounted on both sides of theconnecting base 320. FIG. 36 shows the connecting base 320 separately.An underside of the connecting base 320 is disposed in parallel with aninclined base 361 of the lateral support base 360 when the seat body 310is placed on the ground as a wheelchair. A pair of right and leftconnecting pins 322 and a hook 323 are mounted on the underside of andon the middle of the front end of the connecting base 320, respectively.A flange 322 a having a predetermined diameter is formed on a distal endof each of the connecting pins 322. The function of the flange 322 awill be described below.

As shown in FIG. 35, each of the right and left wheel frames 321 mountedon both sides of the connecting base 320 includes a main arm 324 thatpivots vertically.

The main arm 324 is supported through a shaft 324 a near the rear end ofthe side of the connecting base 320 for vertical pivotal movement. Thefront ends of the main frames 324 are connected by a U-shaped connectingarm 325, and a foot rest 325 a is mounted on the connecting arm 325.

An upper end of a rear wheel arm 326 is connected to the main arm 324near the rear end through a shaft 326 a for vertical pivotal movement. Arear wheel 327 is rotatably supported on the lower end of the rear wheelarm 326. A slot-like connecting groove 326 b is formed in a generallymedial portion of the rear wheel arm 326. A lower end of an auxiliaryarm 328 is connected to the connecting groove 326 b through a shaft 328a for rotation and movement along the groove 326 b. An upper end of theauxiliary arm 328 is pivotally connected to the main arm 324 between theshaft 326 a and the shaft 324 a by a pivot 328 b.

A front wheel 330 is rotatably supported on the front end of the mainarm 324 by a bracket 329. The bracket 329 has a tubular portion 329 a.The tubular portion 329 a is supported around the main arm 324 coaxiallywith and rotatably around the axis of the main arm 324. Thus, thebracket 329 is connected to the main arm 324 to permit rotation aroundthe axis of the main arm 324. Therefore, the front wheel 330 can beextended to an operating position by rotating the bracket 329 downwardlyaround the axis of the main arm 324, while it can be retracted inwardlyof the main arm 324 to a stored position by rotating the bracket 329upwardly around the axis of the main arm 324. FIG. 34 shows the frontwheels 330 in a stored position.

Further, a lower end of a lock arm 331 is rotatably supported on thefront end of the main arm 324 by a shaft 331 a. A hook-shaped portion331 b is formed on the upper end of the lock arm 331. The hook-shapedportion 331 b is removably engaged on a lock pin 332 that is mounted onand extends laterally from the side of the connecting base 320.

The wheel frames 321 thus constructed are connected to each other by theconnecting arm 325 and thus can be retracted together. Specifically, asshown in FIG. 35 by solid line, the main arms 324 are pivoted downwardlyso as to be extended, and then the lock arm 331 is rotated to anupstanding position and the hook-shaped portion 331 b is engaged on thelock pin 332. Thus, the main arms 324 are locked in the extendedposition.

Subsequently, the brackets 329 are rotated downwardly, so that the frontwheels 330 are extended. At the same time, the rear wheel arms 326 arerotated downwardly, so that the rear wheels 327 are extended. With suchrotation of the rear wheel arms 326, each of the auxiliary arms 328 ispivoted downwardly around the pivot 328 b while allowing the shaft 328 ato move relatively along the connecting groove 326 b. Each of the rearwheel arms 326 is pivoted from forward to rearward (from the left to theright as viewed in FIG. 35) beyond a vertical line through the shaft 326a. The auxiliary arm 328 and the main arm 324 form a truss on therearward position and exert a load on the rear wheel arm 326. By thusextending the wheel frames 321, the seat body 310 can be used separatelyas a wheelchair.

The wheel frames 321 are stored when the seat body 310 is moved into thevehicle. Specifically, when the seat body 310, which has been used as awheelchair, is moved into the vehicle, the seat body 310 is connected tothe lateral support base 360 of the lift-up mechanism 350. In thisstate, the wheel frames 321 are stored along the sides of the seatcushion 311. In order to store the wheel frames 321, the hook-shapedportion 331 b of the lock arm 331 is first disengaged from the lock pin332, which allows the main arms 324 to rotate upwardly. Then, the mainarms 324 are rotated upwardly, and at the same time, the brackets 329are rotated upwardly, so that the front wheels 330 are stored betweenthe main frames 324. The stored state of the front wheels 330 is clearlyshown in FIG. 34.

Further, the rear arms 326 are rotated upwardly so as to be storedgenerally along the sides of the seat cushion 311. Wheel covers 333 forcovering the rear wheel arms 326 and the rear wheels 327 are provided onboth sides of the seat cushion 311.

The main arms 324, the front wheels 330 and the rear wheels 327 thusstored, can be retained by respective position retaining means (notshown) in the stored position.

By thus storing the wheel frames 321, the seat body 310 can be installedsubstantially in the same vertical position as other seats in thevehicle (fixed seats in the vehicle, such as a driver's seat) when theseat body 310 has been moved into a specified position in the vehicle.Therefore, the passenger in this rotating seat can sit at the sameheight as the other passengers in the vehicle.

The lift-up mechanism 350 installed within the vehicle will now bedescribed. The lift-up mechanism 350 includes a lateral support base360, a rotating support base 380, and a longitudinal support base 390.The lateral support base 360 connects and supports the seat body 310 topermit sliding movement in the lateral direction of the vehicle. Therotating support base 380 rotatably supports the lateral support base360 and thus supports the seat body 310 to permit rotation between theposition facing the door opening side and the position facing the frontof the vehicle. The longitudinal support base 390 supports the rotatingsupport base 380 and thus the seat body 310 to permit sliding movementin the longitudinal direction of the vehicle.

As shown in FIGS. 37 and 39, the lateral support base 360 includes apair of right and left linear slide mechanisms 362. Each of the linearslide mechanisms 362 includes a fixed rail 362 a, a moving rail 362 band a plurality of steel balls 362 c disposed between V-shaped grooves362 d of the rails 362 a and 362 b.

The inclined base 361 and a connecting frame 369 are mounted on andextend between the moving rails 362 b on the forward portions and on therear ends, respectively.

The inclined base 361 is disposed in parallel to the connecting base 320of the seat body 310. The seat body 310 is superposed on and connectedto the inclined base 361, so that the seat body 310 is connected to thelift-up mechanism 350.

A cutout portion 361 a is formed on a medial portion of the front edgeof the inclined base 361 and receives a hook 323 on the side of the seatbody 310 when the seat body 310 is connected to the lift-up mechanism350. Further, a pair of connecting openings 361 b are formed through theinclined base 361 to the rear of the inclined base 361.

Each of the connecting openings 361 b has a slot shape that is widertoward the exterior side of the vehicle. The wide portion of theconnecting opening 361 b on the exterior side has a width that permitsinsertion of the flange 322 a of the connecting pin 322. A narrowerportion of each of the connecting openings 361 b on the interior sidehas a width that is smaller than the diameter of the flange 322 a andthat permits insertion of a stem of the associated connecting pin 322.

Further, as shown in FIG. 33, the connecting openings 361 b are curvedmore away from the door panel Dr of the vehicle on the exterior sidethan on the interior side.

As shown in FIGS. 38 and 39, a toggle clamp 355 is mounted on theunderside of the inclined base 361 at a position corresponding to thecutout portion 361 a. Further, a hook-shaped stopper 356 is also mountedon the underside of the inclined base 361 inwardly of and beside each ofthe connecting openings 361 b for rotation around a pivot 356 a. Atension spring 357 is disposed between the head portions of the stoppers356, so that a free end of each of the stoppers 356 is biased in adirection that moves across the connecting openings 361 b.

A generally box-like connecting frame 363 is mounted across the rearends of the fixed rails 362 a. As a driving source for the lateralsupport base 360, a motor 364 is mounted to the connecting frame 363.One end of a threaded shaft 365 is connected to the motor 364 via areduction gear train 364 a. Further, the front ends of the fixed rails362 a are also connected to each other by a connecting frame 366. Theother end of the threaded shaft 365 is rotatably supported by a bracket366 a mounted on the connecting frame 366.

A nut 367 is secured to the connecting frame 369 by the bracket 368 andis adapted to engage the threaded shaft 365. When the motor 364 isstarted, the threaded shaft 365 rotates and thus the nut 367 moves alongthe threaded shaft 365. As a result, the moving rails 362 b slide withrespect to the fixed rails 362 a, and thus the inclined base 361 movesin the lateral direction of the vehicle (in the sliding direction of thelinear slide mechanism 362).

An L-shaped bracket 370 is mounted in a generally medial portion in thesliding direction of each of the fixed rails 362 a. The bracket 370 isfixed on a rotating base 371. The lateral support base 360 is mounted onan inner ring 381 of a rotating support base 380, which will bedescribed below, by the rotating base 371.

The rotating support base 380 also incorporates a slide mechanismsimilar to the above-mentioned linear slide mechanism 362. Specifically,V-shaped grooves are formed in the outer peripheral surface of the innerring 381 and in the inner peripheral surface of the outer ring 382,respectively. A plurality of steel balls are disposed between theV-shaped grooves. With the rotating support base 380 thus constructed,the lateral support base 360 and thus the seat body 310 can be rotatedsmoothly without rattling.

As shown in FIG. 40, the rotating support base 380 is mounted on a mainbase 391 of the longitudinal support base 390. The main base 391 ismounted on the vehicle floor F via a pair of right and left linear slidemechanisms 392 to permit longitudinal movement. The linear slidemechanisms 392 are constructed similarly to the above-mentioned linearslide mechanisms 362. Specifically, each of the linear slide mechanisms392 consists of a fixed rail 392 a, a moving rail 392 b and a pluralityof steel balls (not shown) disposed between V-shaped grooves 392 c thatare formed in both rails 392 a,392 b.

A coupling mechanism 395 serves to couple the rotational movement andthe longitudinal sliding movement of the seat body 310. The couplingmechanism 395 consists of a circular-arc pinion gear 396 mounted to theunderside of the rotating base 371, an intermediate gear 397 mounted onthe main base 391 and a rack 398 mounted on the vehicle floor F. Thepinion gear 396 engages the intermediate gear 397, and the intermediategear 397 engages the rack 398.

By engaging the pinion gear 396 with the intermediate gear 397 and theintermediate gear 397 with the rack 398, the seat body 310 slidesforward with respect to the vehicle while rotating. On the other hand,when the seat body 310 is rotated from the door opening side to theposition facing the front of the vehicle, the seat body 310 slidesrearward with respect to the vehicle by coupling with this rotationalmovement. Thus, a wider space can be provided close to the occupant'sfeet. With the coupling mechanism 395 thus constructed, the rotationalmovement and the longitudinal sliding movement of the seat body 310 canbe made in a single operation, thereby making the rotating vehicle seat301 more convenient to use and further simplifying the steps of gettinginto and out of the vehicle.

With the rotating vehicle seat 301 having the above construction, theseat body can be detached from the vehicle so as to be used separatelyas a wheelchair outside the vehicle, as well as a passenger seat insidethe vehicle.

Representative operations for moving the seat unit 310 from the outsideto the inside after having used the seat unit 310 separately as awheelchair, will now be described in further detail. The lateral supportbase 360 is directed to the door opening side (so as to slide in thelateral direction of the vehicle) and the inclined base 361 is moved tothe outside end (to the front). Then, with the wheelchair user sittingin the scat body 310, the seat body 310 is moved backward toward thelateral support base 360 such that the connecting base 320 of the seatbody 310 is superposed on the inclined base 361 of the lateral supportbase 360. The connecting pins 322 of the connecting base 320 areinserted into the connecting openings 361 b of the inclined base 361.

The connecting openings 361 b are curved in a manner that the exteriorside ends are directed rearward of the vehicle, as described above.Therefore, when the connecting pins 322 are inserted into the connectingopenings 361 b, the seat body 310 can be moved toward the lift-upmechanism 350 in a manner to be rotated from behind the door Dr so asnot to interfere with the door Dr.

In this stage of moving the seat body 310 toward the lateral supportbase 360 so as to be rotated from behind the door Dr and inserting theconnecting pins 322 into the connecting openings 361 b, each of theconnecting pins 322 first enters the wider portion of the connectingopening 361 b. As shown in FIG. 38 by a solid line, the wider portion ofthe connecting opening 361 b can receive the flange 322 a of theconnecting pin 322, thereby allowing the connecting pin 322 to beinserted into and removed from the connecting opening 361 b. After theconnecting pin 322 has been inserted into the wider portion, the seatbody 310 is further moved backward to allow the connecting pin 322 to bemoved toward the narrower portion of the connecting opening 361 b. Thewidth of the narrower portion is smaller than the diameter of the flange322 a of the connecting pin 322. Therefore, the flange 322 a interfereswith both sides of the associated connecting opening 361 b, therebypreventing removal of the connecting pin 322 from the connecting opening361 b. As a result, the connecting base 320 is locked in the statesuperposed on the inclined base 361, and thus the seat body 310 islocked in the state connected to the lift-up mechanism 350.

The end portion of each of the stoppers 356 extends across theconnecting opening 361 b as the connecting pin 322 moves from the widerportion to the narrower portion of the connecting opening 361 b.Therefore, the connecting pin 322 moves to the narrower portion of theconnecting opening 361 b, while pushing the end portion of the stopper356 to rotate the stopper 356 around the pivot 356 a in the unlockingdirection (counterclockwise as for the left stopper 356 and clockwise asfor the right stopper 356 as viewed in FIG. 38) against the tensionspring 357.

When the connecting pin 322 moves into the narrower portion whilerotating the stopper 356 in the unlocking direction, the stopper 356rotates in the locking direction (clockwise as for the left stopper 356and counterclockwise as for the right stopper 356 as viewed in FIG. 38)by the tension spring 357. Thus, the end portion of the stopper 356 isreturned to the locking position extending across the connecting opening361 b. When the connecting pin 322 thus enters the narrower portion (asshown by a broken line in FIG. 38), as described above, the flange 322 aof the connecting pin 322 engages both sides of the connecting opening361 b, thus preventing the connecting pin 322 from being removed fromthe connecting opening 361 b. Further, the stopper 356 prevents theconnecting pin 322 from moving to the wider portion. Therefore, theconnecting pins 322 are reliably engaged with the connecting opening 361b.

At the same time that the connecting pin 322 is moved into theconnecting opening 361 b, the hook 323 is inserted into the cutoutportion 361 a of the inclined base 361. When the hook 323 is engagedwithin the cutout portion 361 a and the connecting pin 322 moves intothe narrower portion of the inclined base 361, the connecting base 320is substantially superposed on the inclined base 361. Thereafter, whenan engagement portion 355 a of the toggle clamp 355 is engaged with thehook 323, the connecting base 320 is locked in the state superposed onthe inclined base 361. Thus, the connection of the lift-up mechanism 350to the seat body 310 is completed.

After the seat body 310 has been thus connected to the lift-up mechanism350, the wheel frames 321 are retracted in the aforementioned procedure.Thus, the wheel frames 321 are retracted and stored along the undersideand the sides of the seat cushion 311.

After the seat body 310 has been connected to the lift-up mechanism 350and the wheel frames 321 have been stored, the lift-up mechanism 350 isactuated to move the connected seat body 310 to the inside of thevehicle. Specifically, the motor 364 of the lateral support base 360 isfirst actuated to move the connected seat body 310 to the interior side.When the seat body 310 is moved to the end of the interior side in thelateral direction, the motor 364 is stopped.

Subsequently, the seat body 310 is manually moved from the positionfacing to the door opening side to the position facing to the front ofthe vehicle. Because the lift-up mechanism 350 of this embodiment hasthe coupling mechanism 395 as described above, the seat body 310 movesrearward with respect to the vehicle in synchronization with therotational movement of the seat body 310. When the seat body 310 isrotated to the position facing the front of the vehicle, the seat body310 is moved to the rear end position of the sliding movement by meansof the longitudinal support base 390. Thus, a wider space is providedclose to the occupant's feet. During this process, the wheelchair usercan remain sitting in the seat body 310.

On the other hand, in order to move the seat body 310 from beinginstalled in the vehicle compartment as described above to the outsidefor use as a wheelchair, while the wheelchair user is sitting in theseat body 310, the wheelchair user helper manually rotates the seat body310 by about 90° from the position facing the front of the vehicle tothe door opening side. By coupling with the rotational movement, theseat body 310 moves forward with respect to the vehicle. Subsequently,when the seat body 310 has been rotated to the position facing the dooropening side, the motor 364 of the lateral support base 360 is actuatedto move the seat body 310 to the outside in the lateral direction of thevehicle. After the seat body 310 has been moved to the outside endposition in the lateral direction of the vehicle, the motor 364 isstopped.

After the seat body 310 has been moved to the outside end position inthe lateral direction of the vehicle, the wheel frames 321 are extendedin the above-described procedure.

Subsequently, the toggle clamp 355 is unlocked to disengage theengagement portion 355 a from the hook 323. At the same time, thestoppers 356 are rotated away from the connecting opening 361 b. In thisstate, the seat body 310 is moved forward manually, for example. Whenthe seat body 310 is moved forward, the connecting pin 322 moves the endof the stopper 356 from the narrower portion of the connecting opening361 b toward the wider portion. When the connecting pin 322 moves to thewider portion of the connecting opening 361 b, which wider portion has awidth large enough that the flange 322 a of the connecting pin 322 canbe inserted into the wider portion, the connecting pin 322 is permittedto move out of the connecting opening 361 b. Further, at this stage, thehook 323 is disengaged from the cutout portion 361 a.

After the connecting pin 322 has been permitted to withdraw from theconnecting opening 361 b, the connecting base 320 is moved away from theinclined base 361 by moving the seat body 310 forward. Thus, the seatbody 310 can be detached from the lift-up mechanism 350. The seat body310, which has thus been detached from the lift-up mechanism 350, can beseparately used as a wheelchair.

With the rotating vehicle 301 thus constructed, the seat body 310 can beseparately used as a wheelchair, and when the seat body 310 is connectedas is to the lateral support base 360. and moved into the vehicle, theseat body 310 can be also used as a vehicle seat. Such a rotating seatdoes not require the wheelchair user to change from a vehicle seatinside the vehicle to a wheelchair outside the vehicle and vice versa,thereby making it easier for such a wheelchair user to enter and exit avehicle.

Further, because the seat body can be used separately as a wheelchairand can be moved into the vehicle while keeping the function of awheelchair (mainly a function of moving by means of the seatingmechanism and the wheel frames 321), the rotating seat is moreconvenient to use, compared with a known rotating seat in which awheelchair frame portion is detached when used inside the vehicle.

Further, after having been used as a wheelchair, the seat body 310 canbe connected to the lateral support base 360 by superposing andconnecting the connecting base 320 of the seat body 310 on the inclinedbase 361. The inclined base 361 is downwardly inclined toward theexterior side, and the connecting base 321 is disposed in parallel tothe inclined base 361. With this construction, differences in thevertical position between the seat body 310 and the lateral support base360, if any, existing in the stage of moving the seat body 310 as awheelchair toward the lateral support base 360, can be corrected bysliding contact between the connecting base 321 and the inclined base361 that are parallel to each other. As a result, the seat body 310 canbe easily connected to the lateral support base 360.

Further, the right and left wheel frames 321 mounted on the sides of theseat body 310 can be retracted and stored along the underside and thesides of the seat cushion 311. As a result, the vertical position of theseat body 310 when installed inside the vehicle can be lowered.Therefore, the rotating vehicle seat 301 can be easily installed insidethe vehicle in substantially the same vertical position as other seatsfixed in the vehicle, such as a driver's seat. Consequently, thepassenger can be seated in substantially the same vertical position asother passengers in the vehicle.

Further, with the rotating vehicle seat 301 of this embodiment, becausethe connecting openings 361 b are curved more away from the door panelDr of the vehicle on the exterior side than on the interior side, theseat body 310 can be moved toward the lift-up mechanism 350 in a mannerso as to rotate from behind the door Dr and not interfere with the doorDr. Thus, the seat body 310 can be smoothly connected to and detachedfrom the lift-up mechanism 350 while efficiently using the limitedspace.

Various changes or modifications may be added to the above-describedembodiment. For example, in this embodiment, it has been described thatthe connecting base 320 is superposed on and secured to the inclinedbase 361 by engaging the connecting recess with the connectingprojection, so that the seat body 310 is connected to the lift-upmechanism 350. The means for securing the connecting base to theinclined base may be changed to various other forms. For example, threehooks may be arranged on the connecting base, and three toggle clampsmay be arranged on the inclined base to correspond to the three hooks.The toggle clamps may engage the respective hooks to thereby secure theconnecting base to the inclined base.

Further, although the connecting recess in the form of the connectingopening 361 b has been described as being formed through the inclinedbase 361, even if the engagement between the connecting recess and theconnecting projection is used to secure the connecting base to theinclined base, the connecting recess may not necessarily be formedthrough the inclined base 361, and any recess that can engage theconnecting projection on the seat body side may be used. When theconnecting recess is formed so as not to extend through the inclinedbase 361, the stopper 356 may be disposed on the upper surface of theinclined base.

Further, although the connecting pin as a connecting projection has beendescribed as being provided on the connecting base 320, with theconnecting recess being provided in the inclined base 361, they may beprovided vice versa. Specifically, the connecting projection may beprovided on the inclined base, and the connecting recess may be providedin the connecting base.

An embodiment (a fifth embodiment) of the invention as described inclaim 6 will now be described with reference to FIGS. 41 to 50. FIG. 41shows a rotating vehicle seat 401 of this embodiment. The rotatingvehicle seat 401 has a wheelchair 410 and a lift-up mechanism 450.

The wheelchair 410 includes a seat body 411 having a seat cushion 411 aand a seat back 411 b, a seat frame 420 having a generally L-shaped sidesurface for supporting the seat body 411, and coverings 430 also havinggenerally L-shaped side surfaces and attached to both sides of the seatframe 420.

A footrest 421 is mounted to the front portion of the seat frame 420 viaa pair of support arms 421 a.

A pair of front wheels 422 are mounted to the front ends of the supportarms 421 a. Each of the front wheels 422 is mounted to an end of a frontwheel stay 422 b and swing vertically. The other end of the front wheelstay 422 b is connected to the support arm 421 a by a pivot 422 a, whichpivot 422 a permits the front wheel stay 422 b to swing vertically. Asshown in FIG. 43 by a broken line, by rotating the front wheel stay 422b upward, the front wheel 422 can be stored (retracted) in a wheelstorage section 430 a that is provided in the front portion of thecovering 430. On the other hand, as shown in FIG. 43 by a solid line, byrotating the front wheel stay 422 b downward to be placed on the ground,the front wheel 422 can be allowed to function as a travelling wheel.

A pair of rear wheels 423 are mounted on the rear portion of theunderside of the seat frame 420. As shown in FIG. 43, each of the rearwheels 423 is also mounted to an end of a rear wheel stay 423 b andswing vertically. The other end of the rear wheel stay 423 b isconnected to a lower surface of the frame 420 by a shaft 423 a, whichshaft 423 a permits the rear wheel stay 423 b to swing vertically. Likethe front wheels 422, the rear wheel 423 can be stored in the wheelstorage section 430 a of the covering 430 by rotating the rear wheelstay 423 b upward. Further, the rear wheel 423 can be allowed tofunction as a travelling wheel by rotating the rear wheel stay 423 bdownward to be placed on the ground. In FIG. 43, a broken line depictsthe rear wheel 423 stored in the wheel storage section 430 a, and asolid line depicts the rear wheel 423 extended downward and placed onthe ground.

Although it is not shown, a tension spring is disposed in each of thefront and rear wheel stays 422 b,423 b in a manner that permits thebiasing force to be exerted in both directions for storing and extendingthe wheels. Thus, the front wheels 422 and the rear wheel 423 can beheld in a stored position within the wheel storage section 430 a or inan extended position.

As shown in FIG. 43, a cushion bar 424 that is covered with an elasticrubber is mounted at the back (on the right as viewed in the drawing) ofa shaft 423 a of each of the rear wheels 423. The cushion bar 424 is incontact with the rear wheel stays 423 b of the rear wheels 423 and canabsorb shocks that will be transmitted from the road surface to the rearwheels 423. In other words, the cushion bar 424 functions as a shockabsorber.

Each of the right and left coverings 430 has an upright portion 430 balong the sides of the seat back 411 b. A connecting recess 440 isdefined within each upright portion 430 b and works when the wheelchair410 is connected to the lift-up mechanism 450. The connecting recess 440is defined along the seat frame 420 and has a vertically elongatedcurved configuration having a U-shaped cross section that is open to therear as shown in FIG. 44. As shown in FIGS. 43 and 45, a bent portion440 a is formed on the upper portion of the connecting recess 440 anddefines a catching recess 440 b.

A lock bar 445 is provided in the lower portion of each connectingrecess 440 on the each side of the seat frame 420 and can lock theconnection between the wheelchair 410 and the lift-up mechanism 450. Asshown in FIG. 46, a retaining bracket 446 supports each of the lock bars445 and permits vertical movement. A vertically extending guide slot 446a is formed in the retaining bracket 446 and receives a guide pin 445 amounted on the lock bar 445. Thus, the lock bar 445 is permitted to movevertically within the range in which the guide pin 446 a can move in theguide slot 446 a.

A lock retaining portion 446 b is formed by making a cut in the upperend of the guide slot 446 a of the retaining bracket 446 in a directiongenerally perpendicular to the slot 446 a. When the lock bar 445 ismoved upward to the upper end and then rotated around its axis by about90°, the guide pin 445 a enters the lock retaining portion 446 b throughthe guide slot 446 a, thereby holding the lock bar 445 in the upper endlocking position. When the lock bar 445 is held in the upper end lockingposition, as will be described below, a lower end portion 456 d of theconnecting plate 456 of the lift-up mechanism 450 is locked to preventmovement, and thus the connection of the lift-up mechanism 450 islocked. In order to release this locked state, the lock bar 445 isrotated in the reverse direction to move the guide pin 445 a from insidethe lock retaining portion 446 b into the guide slot 446 a, and then,the lock bar 445 is allowed to move downwardly under its own weight.

As shown in FIGS. 43 and 46, an upper end portion 445 b of the lock bar445 has a conical shape so as to fit with the lower end portion 456 d ofthe connecting plate 456. Further, a lower end portion of the lock bar445 is bent into an L-shape, and may be conveniently used to rotate thelock bar 445 by about 90° as described above. Connecting anddisconnecting operations for the lift-up mechanism 450 will be furtherdescribed below.

A pair of arm rests 411 c are provided on both sides of the seat back411 b in a manner that permits vertical pivotal movement so as to storeand extend the arm rests 411 c. Further, a head rest 411d is provided onthe top of the seat back 411 b. Further, as shown in FIGS. 41 and 42, ahandle 412 is mounted on the back of the seat frame 420 to be operatedby the passengers' helper. The handle 412 is formed by bending a pipeinto a U-shape, and is connected to extend across both sides of the seatback 411. A brake lever 412 a for operating a brake for the rear wheelsis mounted on the side of the handle 412. In FIG. 43, the handle 412 isnot shown.

The lift-up mechanism 450 installed inside the vehicle will now beexplained in further detail. The lift-up mechanism 450 includes a mainbase 452, a rotary disc 453, a swing base 454, and a pair of quadriclink mechanisms 455. A pair of slide rails 451 are installed on thevehicle compartment floor F and longitudinally movably support the mainbase 452. The rotary disc 453 is mounted on the main base 452 and theswing base 454 is mounted on the rotary disc 453. The link mechanisms455 are provided on both sides of the swing base 454.

In this embodiment, a drive mechanism for moving the main base 452longitudinally with respect to the vehicle is not provided. Therefore,the main base 452 is manually moved longitudinally with respect to thevehicle. The main base 452 can be locked at a desired position in thelongitudinal direction of the vehicle by a slide lock mechanism (notshown). An electrically powered drive mechanism, such as the combinationof a motor and a rack and pinion device, may be used to move the mainbase 452 longitudinally with respect to the vehicle.

An inner ring 453 a and an outer ring 453 b are assembled together toform the rotary disc 453 and to permit rotation with respect to eachother. The outer ring 453 b is fixed on the main base 452 and the innerring 453 a is fixed on the underside of the swing base 454. The swingbase 454 is supported by the rotary disc 453 to permit rotation of about90° between the position facing the front of the vehicle and theposition facing the lateral side of the vehicle (facing the door openingD; see FIGS. 41 and 42). The swing base 454 can be locked in the twopositions, one facing the front of the vehicle and the other facing thelateral side of the vehicle, by a rotation lock mechanism (not shown).

Further, as shown in FIG. 49 (not shown in FIG. 47), an arc-shapedpinion gear 454 a is mounted on the underside of the swing base 454, anda rack 451 a is disposed on the vehicle interior floor F along the sliderail 451 on the door opening side (the lower one in FIG. 49) and engagesthe pinion gear 454 a. With this arrangement, the rotational movement ofthe swing base 454 is coupled to the sliding movement of the main base452. Specifically, when the wheelchair 410 inside the vehicle is rotatedfrom the position facing the front of the vehicle toward the dooropening D, because the pinion gear 454 a does not have any engagementteeth on the initial engagement side as shown in FIG. 49, only the swingbase 454 rotates at the beginning of rotation. After the wheelchair 410has been rotated by a predetermined angle, the pinion gear 454 a startsto engage the rack 451 a. Thus, the rotational movement of the swingbase 454 is thereafter coupled to the forward sliding movement of themain base 452. As a result, the wheelchair 410 moves forward withrespect to the vehicle while rotating to the door opening D. With such acoupling mechanism, by a simple rotational operation without the needfor a forward sliding operation, the wheelchair 410 can be moved to aproper position to be extended to the exterior side, thereby making thewheelchair more convenient to use. Similarly, when the wheelchair 410 isrotated from outside to inside the vehicle by a simple rotationaloperation toward the front of the vehicle, the wheelchair 410 can bemoved rearward with respect to the vehicle. By such a rearward slidingmovement of the wheelchair 410, a wider space can be provided close tothe occupant's feet.

Each of the quadric link mechanisms 455 has two link arms 455 a and 455b. The lower ends of the front link arms 455 a are connected by pivots455 c to both side portions of the swing base 454 to permit verticalrotation. The lower ends of the rear link arms 455 b are connected by aconnecting rod 457. Thus, the link arms 455 b rotate vertically withrespect to the swing base 454 via the connecting rod 457.

An electric cylinder 490 is connected to the connecting rod 457 andserves as a drive source for driving the link mechanisms 455. Theelectric cylinder 490 will be described below in detail.

The connecting plate 456 is connected to the distal end of each linkmechanism 455. The link arms 455 a and 455 b are pivotally connected tothe connecting plate 456 via pivots 456 a and 456 b.

As shown in FIGS. 43 and 44, the connecting plate 456 has a generallyflat plate-like shape and can be inserted into the connecting recess 440of the wheelchair 410 without providing substantially any clearance.Further, as shown in FIG. 45, the upper portion 456 c of the connectingplate 456 is shaped so as to permit insertion into the catching recess440 b of the connecting recess 440 without providing any clearance. Whenthe upper portion 456 c of the connecting plate 456 is inserted into thecatching recess 440 b, a bent portion 440 a prevents the upper portion456 c from displacing in a disengaging direction (in a rightwarddirection as viewed in FIG. 43).

Further, the upper end 445 b of the lock bar 445 is pressed against thelower end portion 456 d of the connecting plate 456, thereby preventingthe lower end portion 456 d from displacing in a disengaging direction(in a rightward direction in FIG. 43). Thus, the connecting plate 456 isprevented from being removed from the connecting recess 440, and thewheelchair 410 is connected to the lift-up mechanism 450.

The electric cylinder 490 is shown in detail in FIG. 48. Two L-shapedsupport arms 459 are fixed in a generally medial portion of theconnecting rod 457, and the electric cylinder 490 is mounted to theconnecting rod 457 via the support arms 459. The electric cylinder 490essentially consists of an electric motor 491, a gear box 492 and a ballscrew 494. The ball screw 494 includes a threaded shaft 494 a and ablock-shaped nut 494 b threadably engaged with the threaded shaft 494 a.When the motor 491 is started, the threaded shaft 494 a rotates bytorque amplified by means of the gear box 492 and thus the nut 494 bmoves axially with respect to the threaded shaft 494 a.

The threaded shaft 494 a is rotatably supported by a cylindricalthreaded shaft case 493 mounted on the gear box 492. The threaded shaftcase 493 is supported between the ends of the support arms 459 via theshafts 459 a for vertical pivotal movement. Further, two plate-likebrackets 495 are mounted on both side surfaces of the nut 494 b. A frontend of each of the brackets 495 is connected by a shaft 496 to thebottom of the swing base 454 near a front end thereof for verticalpivotal movement.

With the electric cylinder 490 thus assembled, when the motor 491 isrotated in a forward direction with the wheelchair 410 being held facingthe door opening D, the threaded shaft 494 a rotates and thus the nut494 b moves relative to the threaded shaft 494 a toward the front end ofthe threaded shaft 494 a. However, because the nut 494 b is fixed by thepivots 496 between the support arms 495 that can pivot vertically, thethreaded shaft 494 a eventually moves rearward in the axial direction(upward as viewed in FIG. 48) while rotating. The threaded shaft case493 also moves rearward together with the threaded shaft 494 a. Thus,the support arms 459 and the connecting rod 457 rotate in the directionshown by arrow A in FIG. 48. As a result, the rear link arms 455 b andthus the quadric link mechanisms 455 pivot in the direction shown byarrow C in FIG. 47 (toward the outside of the vehicle), which movementis an extending movement of the link mechanisms 455 toward the outsideof the vehicle. By this extending movement, the connecting plates 456are moved to the outside of the vehicle through the door opening D.

When the motor 491 is then rotated in a reverse direction, the threadedshaft 494 a moves forward in the axial direction (downward as viewed inFIG. 48) and the connecting rod 457 rotates in the direction shown byarrow B in FIG. 48. As a result, the quadric link mechanisms 455 pivotin the direction shown by arrow D in FIG. 47 (toward the inside of thevehicle), and thus the connecting plates 456 are moved back to theinside of the vehicle.

Representative operations for connecting and detaching the wheelchair410 using the lift-up mechanism 450 will now be described in furtherdetail. The following operations can be performed with the wheelchairuser sitting in the scat body 411, and the wheelchair user can be movedto a specified position in the vehicle compartment while sitting in theseat body 411.

In FIG. 41, the wheelchair 410 is shown as being detached from thelift-up mechanism 450. In the lift-up mechanism 450, the main base 452is shown moved to the front end of the slide rails 451 and the swingbase 454 is directed to the exterior side. The quadric link mechanisms455 are shown rotated to the extended position. In the wheelchair 410,on the other hand, the front and rear wheels 422 and 423 are shownextended from the wheel storage section 430 a in a state in which thewheelchair 410 can be used separately, that is, the wheelchair 410 isready for use as a normal wheelchair on the roads. As mentioned above,the wheelchair user remains sitting in the seat body 411.

The wheelchair 410 can be connected to the lift-up mechanism 450 andmoved inside the vehicle by the following representative procedure.First, the wheelchair 410 is placed sufficiently close to the lift-upmechanism 450 with its back toward the lift-up mechanism 450. Theconnecting plates 456 of the lift-up mechanism 450 are then insertedinto the connecting recesses 440 of the wheelchair 410. Thereafter, theelectric motor 491 of the electric cylinder 490 is rotated in a reversedirection, so that the link mechanisms 455 slightly pivot toward theraised position. The upper portions 456 c of the connecting plates 456are then inserted into the catching recesses 440 b of the connectingrecesses 440.

Subsequently, the lock bars 445 are moved upward such that the upper endportion 445 b abuts against the lower end portion 456 d of theconnecting plate 456. Thereafter, the lock bar 445 is rotated around itsaxis by about 90° so as to allow the guide pin 445 a to enter the lockretaining portion 446 b. Thus, the lock bar 445 is held in the upper endlocking position. By the above-described operation of the lock bar 445,the upper end portion 445 b and the lower end portion 456 d of theconnecting plate 456 are locked to prevent movement by the catchingrecess 440 b and the lock bar 445, respectively. Thus, the connectingplate 456 is fixedly connected to the back of the wheelchair 410.

After the lift-up mechanism 450 has been thus connected to thewheelchair 410, the electric cylinder 490 of the lift-up mechanism 450is actuated to move the link mechanisms 455 toward the raised position(toward the interior side). As a result, the wheelchair 410 is lifted upabove the ground. At this stage, the lift-up mechanism 450 is stoppedand the front and rear wheels 422,423 are stored in the wheel storagesection 430 a. This state is shown in FIG. 42.

After the front and rear wheels 422,423 have been stored, the lift-upmechanism 450 is again moved toward the interior side to move theconnected wheelchair 410 into the inside of the vehicle. As shown inFIG. 47, when the quadric link mechanisms 455 are moved to the raisedposition and the wheelchair 410 is moved substantially above the swingbase 454, the electric cylinder 490 is stopped to stop the lift-upmechanism 450. At this stage, the quadric link mechanisms 455 are lockedin the raised position by a swing lock mechanism (not shown), and thusthe wheelchair 410 is held above the swing base 454.

After the wheelchair 410 has thus been moved into the vehiclecompartment, the wheelchair 410 and the swing base 454 are manuallyrotated together by about 90° so as to face the front of the vehicle. Atthis time, as described above, by engaging the pinion gear 454 a withthe rack 451 a, the wheelchair 410 slides rearward with respect to thevehicle while rotating to the position facing the front of the vehicle.Also in this stage, the wheelchair user remains sitting in the seat body411. Therefore, by the above-described operations, the wheelchair useris brought into the seated position facing the front of the vehicle in aspecified position within the vehicle.

On the other hand, by reversing the above-described procedure, thewheelchair 410 can be moved from the specified position within thevehicle to the outside of the vehicle. Also in this procedure, thewheelchair user may remain sitting in the seat body 411, and need notmove from a vehicle seat to a wheelchair. With the wheelchair usersitting in the seat body 411, the wheelchair 410 is moved forward withrespect to the vehicle while being rotated to the door opening side.Thereafter, the lift-up mechanism 450 is moved to the extended positionto move the wheelchair 410 to the outside. When the wheelchair 410 hasbeen moved all the way to the outside, the lift-up mechanism 450 isstopped and the front and rear wheels 422,423 are extended. Thereafter,the lift-up mechanism 450 is again moved to the extended position toplace the wheelchair 410 on the ground.

After the wheelchair 410 has been placed on the ground, the lift-upmechanism 450 is again stopped and the lock bar 445 is moved downward torelease the lock of the connecting plate 456. In this unlocked state,when the lift-up mechanism 450 is again extended, the connecting plate456 moves downward. Thus, the lower end portion 456 c is disengaged fromthe catching recess 440 b. At this stage, the wheelchair 410 is movedforward so that the wheelchair 410 is detached from the lift-upmechanism 450.

The wheelchair 410 thus detached from the lift-up mechanism 450 can bemoved separately and used just like a normal wheelchair.

As described above, with the rotating vehicle seat 401 according to thisembodiment, the wheelchair 410 that can be used as a normal wheelchair,can be moved as a whole (retaining the seat frame 420, the front andrear wheels 422,423, etc.) into the vehicle and can be used as apassenger seat in the vehicle. Without switching from a vehicle seat toa wheelchair or vice versa, the wheelchair user can be seated in aspecified position in the vehicle compartment and can also move from theseated position in the vehicle to the outside. Thus, the wheelchair usercan remain sitting in the seat body 411 of the wheelchair 410, therebymaking it easier for such a passenger to enter and exit a vehicle andmaking such a wheelchair more convenient to use.

Further, with the construction in which the entire wheelchair 410 ismoved by the lift-up mechanism 450, separation and reassembly of theseat body are not required, although such operations were required in aknown construction in which the wheelchair must be separated into theseat body and the wheel side section and only the seat body moves intothe vehicle. Also in this respect, such a wheelchair is more convenientto use. Moreover, the labor of separately loading the separated wheelside section into the vehicle is not necessary.

Further, with the construction in which the connecting recesses 440 areprovided on both sides of the seat back to engage the connecting plates456, the seat back can recline.

Another example of the lock bar 445 will now be explained. Although theabove-described lock bar 445 is constructed to be moved vertically bymanual operation so as to lock and unlock the connecting plates 456, thelock bar may be constructed such that the locking and unlockingoperations are coupled to the retracting and extending operations of therear wheels 423. This example is shown in FIG. 50. Components having thesame construction as in the above-described example will not bedescribed and are identified by the same numerals.

A cam plate 480 is mounted on the side of each of the rear wheel stays423 b that can be vertically rotated by the shaft 423 a . A circular-arccam surface 480 a is formed on the upper surface of the cam plate 480.The cam surface 480 a extends away from the center of rotation of therear wheel stay 423 b (the shaft 423 a) and is displaced downward as therear wheel stay 423 b is rotated downward. A lock bar 481 is mountedabove the cam surface 480 a.

The lock bar 481 is supported on the each side of the seat frame 420 bya bracket 482 to permit vertical movement. A guide roller 484 isrotatably mounted on the lower end of each lock bar 481 via a retainingblock 483. A compression spring 485 is disposed between the retainingblock 483 and the bracket 482 and urges the lock bar 481 downward. Theguide roller 484 is pressed against the cam surface 480 a of the camplate 480 by the biasing force of the compression spring 485.

A lock block 486 is mounted on a lower portion of each of the connectingplates 456 and has a lock hole 486 a for receiving the lock bar 481.

As shown in FIG. 50 by a broken line, when the rear wheels 423 areextended by rotating the rear wheel stays 423 b downward, the camsurface 480 a is positioned in the lowermost position. Thus, the guideroller 484 pressed against the cam surface 480 a, and thus the lock bar45 are held in the lowermost position (unlocked position). Therefore,the upper end of the lock bar 481 is away from the lock hole 486 a ofthe lock block 486.

In this state, the connecting plates 456 are inserted in the connectingrecesses 440 by moving the wheelchair 410 backward, and thereafter, thelift-up mechanism 450 is actuated to move the connecting plates 456upward. Thus, the upper portions 456 c of the connecting plates 456 areinserted into the catching recesses 440 b, thereby preventing therearward displacement of the connecting plates 456. This point is thesame as the above-described first example of this embodiment.

After the upper portions 456 c of the connecting plates 456 are insertedinto the catching recesses 440 b, the lift-up mechanism 450 is furthermoved to the inside of the vehicle, so that the front and rear wheels422,423 of the wheelchair 410 are raised. In this state, the front andrear wheels 422,423 are stored in the wheel storage section 430 a of thecovering 430. At this time, when the rear wheel stays 423 b are rotatedupward, each of the cam surfaces 480 a is relatively displaced upwardly,thereby moving the lock bar 45 upward against the biasing force of thecompression spring 485. As shown in FIG. 50 by a solid line, when therear wheel stays 423 b are rotated to bring the rear wheels 423completely into the stored state, each cam surface 480 a is relativelydisplaced to the uppermost position. Thus, the lock bar 481 is moved tothe upper moving end and the upper end of the lock bar 481 is insertedinto the lock hole 486 a of the lock block 486.

When the upper end of the lock bar 481 is inserted into the lock hole486 a of the lock block 486, the lower end of the connecting plate 456is prevented from displacing rearward (to the right as viewed in FIG.50). Consequently, the connecting plates 456 are securely held withinthe connecting recesses 440. Thereafter, by operating the lift-upmechanism 450 as described above, the wheelchair 410 can be moved fromthe outside to a specified position inside the vehicle.

On the other hand, when the wheelchair 410 is moved from the inside tothe outside of the vehicle and then the rear wheels 423 are extended,the cam surface 480 a is relatively displaced downward. Thus, the lockbar 481 is moved downward by the biasing force of the compression spring485. As a result, the upper end of the lock bar 481 is removed from thelock hole 486 a of the lock block 486, thereby releasing the lock of thelower end of the connecting plate 456.

Thus, each lock bar 481 is moved upward or downward in synchronizationwith retracting or extending operation of the rear wheels 423. As aresult, the lower end of the connecting plate 456 is locked or unlocked.Therefore, unlike the lock bar 445, the lock bar 481 does not requiredirect operation by the user. In this respect, usability of the rotatingvehicle seat 401 can be further improved. With respect to the lockingand unlocking operations, it may be constructed such that only thelocking operation is coupled to the retracting operation of the wheels(the rear wheels 423) and the unlocking operation is manually performedseparately.

Further, although in the above embodiment, the connecting recesses 440are provided on both sides of the seat body 411, they may be provided atother location such as on the back of the seat back. Or, the connectingrecess may be provided at one location on the center of the back of theseat back, instead of being providing at two locations. In this case, itcan be constructed such that the ends of the link mechanisms 455 of thelift-up mechanism are connected to each other and one connecting plateis provided on the middle of this connecting portion. The one connectingplate is adapted to be inserted into the connecting recess that isprovided at one location on the center of the back of the seat back.Further, the number of quadric link mechanisms of the lift-up mechanismmay be one, instead of two.

An embodiment of the invention as defined in claim 7 (a sixthembodiment) will now be explained with reference to FIGS. 51 to 54. Arotating vehicle seat 501 according to the sixth embodiment includes aseat body 502, a lift-up mechanism 550 for moving the seat body 502 fromthe vehicle compartment floor to the outside of the vehicle and viceversa, a rotating support base for rotatably supporting the seat body502 and the lift-up mechanism 550, and a longitudinal support base formoving the seat body 502, the lift-up mechanism 550 and the rotatingsupport base longitudinally with respect to the vehicle. The lift-upmechanism 550 is shown in detail in FIG. 51.

With respect to the lift-up mechanism 550, description concerning thesame aspects as the first embodiment will be omitted. The rotatingsupport base and the longitudinal support base are identical to those ofthe first embodiment and thus, such description will be omitted.

In the sixth embodiment, the seat body 502 is mounted on a base 553 ofthe lift-up mechanism 550 via the quadric link mechanism. The seat body502 has a seat cushion 502 a and a seat back 502 b, and the seat body502 is mounted on a seat holder 521.

As shown in FIG. 51, the seat holder 521 has a generally frame-likeconfiguration that comprises a pair of generally L-shaped side plates522, a flange portion 522 b extending inwardly along the lower edge of ahorizontal portion 522 a of each of the side plates 522, and front andrear horizontal frames 523 a,523 b connecting the front and rear ends ofthe underside of the flange portions 522 b, respectively. Each of theside plates 522 has an inclined portion 522 c integrally formed on theproximal end of the horizontal portion 522 a of the side plate 522 andis configured to extend along the side surface of the seat back 502 b ofthe seat body 502. Two pin holes 522 d are formed in the upper portionof each of the inclined portions 522 c at a predetermined spacingtherebetween. The pin holes 522 d are used to connect the seat holder521 to the quadric link mechanism of the lift-up mechanism 550. A lockbolt 524 having a predetermined length extends outwardly from a medialportion between the pin holes 522 d. Hooks 525 are mounted on the frontand rear horizontal frames 523 a, 523 b with a predetermined spacing andserve to detachably connect the seat holder 521 to a wheelchair 590which will be described below. Further, a footrest 526 for resting theoccupant's feet thereon is retractably mounted to a generally medialportion of the front horizontal frame 523 a (see FIG. 54).

The seat body 502 thus connected to the seat holder 521 is detachablyconnected to the lift-up mechanism 550. As shown in FIG. 51, the lift-upmechanism 550 essentially consists of a pair of right and left quadriclink mechanisms. The lift-up mechanisms 550 serve to move the seat body502 together with the seat holder 521 from the inside to the outside ofthe vehicle and vice versa by extending and retracting the pair ofquadric link mechanisms. Each of the quadric link mechanisms has a firstlink arm 551 and a second link arm 552. The link arms 551 and 552 areconnected to side walls 553 a of the base 553 of the lift-up mechanism550 through pivots 551 a and 552 a, respectively, for pivotal movementin the longitudinal direction of the vehicle. The rear second link arms552 are connected by connecting rods 554,555 and pivot together. Theends of the lower connecting rods 554 are pivotally supported withrespect to the side walls 553 a of the base 553 and thus the axis of theconnecting rod 554 forms the pivotal fulcrum or pivot 552 a of thesecond link arm 552.

As shown in FIGS. 52 and 53, the distal ends of the first and secondlink arms 551 and 552 are removably connected to the seat holder 521. Inorder to provide such connection, insertion sleeves 551 b,552 b areintegrally formed with the first and second link arms 551 and 552 andextend inwardly from a predetermined position on the distal ends of thelink arms 551, 552. The insertion sleeves 551 b,552 b are adapted torotatably fit into the pin holes 522 d of the side plates 522 of theseat holder 521. Further, a generally rectangular connecting arm 556having insertion holes connects the insertion sleeves 551 b and 552 b,so that the insertion sleeves 551 b,552 b can be fitted into the pinholes 552 d of the seat holder 521. Further, an insertion hole 556 a isformed on a generally medial portion of the connecting arm 556 such thatthe lock bolt 524 extending from the side plate 522 extends through theinsertion hole 556 a. On the other side of the link arms 551,552opposite from the side having the connecting arm 556, an anchor plate557 is provided to connect and disconnect the four-join link mechanismto and from the seat holder 521.

As shown in FIG. 52, the anchor plate 557 has a generally rectangularshape substantially corresponding to the connecting arm 556. Two anchorpins 557 a having a predetermined length extend from one side of theanchor plate 557 with a predetermined spacing therebetween and areinserted into the insertion sleeves 551 b,552 b of the link arms 551,552. An insertion hole 557 b is formed between the anchor pins 557 athrough the anchor plate 557, through which hole 557 b the lock bolt 524extending from the side plate 522 extends. On the side of the distalends of the link arms 551, 552 having the above-described arrangement,the lock bolt 524 of each of the side plates 522 of the seat holder 521is inserted through the insertion hole 556 a of the connecting arm 556,with the seat body 502 mounted on the seat holder 521. And, theinsertion sleeves 551 b,552 b are fitted into the pin holes 522 d. Inthis state, the anchor pins 557 a of the anchor plate 557 are insertedinto the insertion sleeves 551 b,552 b from the outside. At this time,the lock bolt 524 is inserted through the insertion hole 557 b. Then, alock knob 558 is threadably engaged on the lock bolt 524 protruding fromthe insertion hole 557 b. Thus, the seat holder 521, with the seat body502 mounted thereon, is connected to the distal ends of the right andleft quadric link mechanisms.

Two L-shaped support arms 559 are fixed in a generally medial portion ofthe lower connecting rod 554. An actuator 560 is mounted between thequadric link mechanisms and the vehicle floor by the support arms 559and serves as a driving source for the lift-up mechanism 550. The drivesystem of the lift-up mechanism 550, including the actuator 560, isidentical to that of the first embodiment and the description will beomitted.

With the drive system including the actuator 560, when an electric motor561 is rotated in a forward direction with the seat body 502 being heldfacing the door opening side, the second link arms 552 pivots about thepivots 552 a toward the outside of the vehicle (to the left as viewed inFIG. 51).

When the second link arms 552 pivot toward the outside of the vehicleand thus the first link arms 551 pivot likewise via the connecting arms556 and the anchor plate 557, the seat holder 521 (the side plate 522)is extended toward the outside of the vehicle along a specified path.When the seat holder 521 is thus extended, the seat body 502 moves fromthe seated position inside the vehicle to a lower outside position. Whenthe motor 561 is then rotated in a reverse direction, the seat holder521 moves backward along the above-mentioned specified path, so that theseat body 502 is moved from the lower outside position back to theseated position inside the vehicle.

A wheelchair 590 will now be described. The wheelchair 590 is designedfor the seat body 502 that is removably connected to the lift-upmechanism 550 via the seat holder 521. The wheelchair 590 is of a commontype in most points, in which leftright symmetric body frames 591, asshown in FIG. 54, are connected by a cross bar (not shown) andconstructed to hold and carry the seat holder 521 with the seat body 520mounted thereon. The wheelchair 590 folds laterally inwardly.

Each of the body frames 591 includes a front frame 592, a rear frame 593and a seat frame 594 extending horizontally across the frames 592,593 ata predetermined vertical position. Although it is not shown, an armframe is provided above the seat frame 594. Further, the rear frame 593extends upwardly and has a handle portion 595 formed on the upper end. Alower frame 596 is provided below the seat frame 594 and is bent. Thefront end of the lower frame 596 is connected to a lower portion of thefront frame 592. The rear portion of the lower frame 596 is connected tothe lower end of the rear frame 593 and further extends rearward by apredetermined length, thus forming an extending portion 596 b. A caster597 is connected to the lower end of the front frame 592 via a bearing,and a large wheel 598 is rotatably connected to the rear frame 593 at apredetermined vertical position.

The right and left body frames 591 thus constructed are connected toeach other by the cross bar to permit folding. Lever latches 599 aremounted in a predetermined position on the upper portions of the frontframes 592 and the rear frames 593 and engage the hooks 525 on the frontand rear frames 523 a , 523 b of the seat holder 521.

The operation procedures in the inside of the vehicle of rotating andmoving the rotating vehicle seat 501 thus constructed are the same asthe first embodiment and such description will be omitted.

When the seat body 502 is rotated to the door opening D(counterclockwise to the position shown in FIG. 11(C)), the operatorgets the wheelchair 590 ready for use and places the wheelchair 590 bythe door opening D near a position to which the seat holder 521 with theseat body 502 mounted thereon will reach down. Thereafter, the electricmotor 561 on the lift-up mechanism 550 is rotated in the normaldirection to extend the seat holder 521 to the exterior side by means ofthe quadric link mechanisms so as to move the seat body 502 from theinterior side position W0 to the exterior side position W1 (see FIG.11). In this process, the seat body 502 is lowered down to a specifiedlevel while moving to the exterior side position W1. Thus, the front andrear frames 523 a,523 b of the seat holder 521 are placed on the rightand left seat frames 594 of the wheelchair 590. After the seat body 502has been lowered down to the specified level outside, the electric motor561 and thus the lift-up mechanism 550 are stopped.

In this state, the latches 599 mounted on the front frames 592 and therear frames 593 of the wheelchair 590 are engaged with the hooks 525 onthe seat holder 521. Then, the lock knobs 558 on the distal ends of thelink arms 551,552 are removed, and the anchor plates 557 are removed. Inthis state, the wheelchair 590 is moved forward so that the seat holder502 with the seat body 502 mounted thereon is separated from the distalends of the quadric link mechanisms. The anchor pins 557 a of theremoved anchor plates 557 are inserted into the pin holes 522 d of theseat holder 521, and the lock knobs 558 are threadably engaged on thelock bolts 524 protruding from the insertion holes 557 b. Thus, theanchor plates 557 are fixedly attached on the seat holder 521. Thus, thepassenger in the seat body 502 can be moved onto the wheelchair 590while sitting inside the vehicle, and can use the wheelchair 590 to movearound.

In order to move the seat holder 521 together with the seat body 502 inwhich the passenger is sitting from the wheelchair 590 back to thevehicle, the passenger's helper rotates the quadric link mechanisms ofthe lift-up mechanism 550 from the door opening D toward the outside ofthe vehicle, and to a position in which the seat holder 521 wasdetached. Then, the right and left anchor plates 557 attached on theseat holder 521 of the wheelchair 590 are removed together with the lockknobs 558. The upper portions of the inclined frames 522 c of the rightand left side plates 522 are then positioned between the connecting arms556 that are connected between the distal ends of the link arms 551,552.The pin holes 522 d are aligned and engaged with the insertion sleeves551 b,552 b. Subsequently, the anchor pins 557 a of the anchor plates557 are inserted into the pin holes 522 d of the seat holder 521, andthe lock knobs 558 are threadably engaged on the lock bolts 524. Thus,the seat holder 521 with the seat body-502 mounted thereon is connectedto the distal ends of the quadric link mechanisms. In this state, thelatches 599 of the wheelchair 590 are disengaged from the hooks 525 onthe seat holder 521.

In order to return the seat body 502, which has thus been moved to theexterior side position W1, to the original seated position, the electricmotor 561 is rotated in the reverse direction to move the lift-upmechanism 550 in the backward direction. Thus, the seat body 502 isreturned to the interior side position W0 while being moved upward. Whenthe seat body 502 has been returned to the interior side position W0,the electric motor 561 and thus the lift-up mechanism 550 are stopped.Thereafter, the rotation lock mechanism, which is not shown, is releasedand the seat body 502 is manually rotated to the interior side. Thus,the passenger can leave the wheelchair 590 and get into the vehiclewhile sitting in the seat body 502 mounted on the seat holder 521.

Thus, the seat holder 521 with the seat body 502 mounted thereon, can bemoved by the lift-up mechanism 550 from the vehicle compartment floor tothe extended position outside the vehicle and vice versa, and canfunction as a seat section of the wheelchair 590 when detached from thelift-up mechanism 550. Therefore, the passenger can move together withthe seat holder 521 onto the seat frame 594 of the wheelchair 590 whichis standing by outside the vehicle, while sitting in the seat body 502.Also, the passenger can move together with the seat holder 521 from thewheelchair 590 into the vehicle while sitting in the seat body 502. As aresult, the passenger's helper does not need to help the passenger totransfer from and to the wheelchair, so that the helper's labor can begreatly reduced.

Further, because the seat body 502 forms the seat section of thewheelchair 590 together with the seat holder 521, the ride comfort ofthe wheelchair 590 can be improved.

Additionally, the connecting and disconnecting structure of the seatholder 521 is very simple in construction, which consists of the seatholder 521, the anchor plates 557, the lock bolts 524 and the lock knobs558. Therefore, such a structure can be readily applied to existinglift-up mechanisms.

An embodiment of the invention as defined in claim 9 (a seventhembodiment) will now be explained with reference to FIGS. 55 to 61. Theseventh embodiment of this invention relates to a vehicle rotating seatin which the seat body can be moved laterally with respect to thevehicle by means of a swing mechanism that essentially consists of aquadric link mechanism, and more particularly, to a swing lock mechanismfor locking the swing movement of the seat body in the rotating seat.

A vehicle rotating seat is well known which includes a rotary discdisposed on a vehicle compartment floor, a lateral slide mechanismmounted on the rotary disc, and a swing mechanism that essentiallyconsists of a quadric link mechanism. In the known rotating seat, theseat body is directed to the door opening side by the rotary disc, andin this state, the seat body is moved laterally with respect to thevehicle to the exterior side by means of the lateral slide mechanism,and thereafter, the seat body is moved to the outside of the vehiclethrough the door opening.

With this known rotating seat, the passenger only has to get in and outof the seat body outside the vehicle, and does not need to move himselfor herself to get into or out of the vehicle. Therefore, the passengercan easily get into or out of the vehicle.

In this known rotating seat, however, the seat body is locked to preventsliding movement only at the rear end in the interior side of thelateral slide mechanism. Therefore, when the seat body slides forward ofthe vehicle in the position facing the front of the vehicle (in whichposition the lateral slide mechanism extends longitudinally with respectto the vehicle), the slide lock is released. Consequently, in the knownrotating seat, the above-described lateral slide mechanism cannot beutilized as a mechanism for adjusting the position of the seat body inthe longitudinal direction of the vehicle.

The invention as described in claim 9 has been made in view of the aboveproblem, and its object is to provide a rotating vehicle seat whichincludes a swing lock mechanism that can maintain the swing lockingstate irrespective of the sliding position of the lateral slidemechanism, whereby, in the state in which the seat body is in theposition facing the front of the vehicle and the swing locking state ismaintained, the lateral slide mechanism can be utilized to adjust theposition of the seat body in the longitudinal direction of the vehicle.

FIG. 55 schematically shows a structure of a rotating vehicle seat 601according to the seventh embodiment of the invention. In FIG. 55, theright-left direction as viewed in the drawing corresponds to the lateraldirection with respect to the vehicle, and the direction perpendicularto the plane of the drawing corresponds to the longitudinal direction ofthe vehicle. Accordingly, in FIG. 55, a seat body 601 is shown in theposition facing the lateral side of the vehicle or the door openingside.

The basic components of the rotating vehicle seat 601 do not require anyparticular modifications in this embodiment, but will now be brieflyexplained. Designated by numeral 602 are a pair of longitudinal sliderails mounted on the vehicle floor F and extending in the longitudinaldirection of the vehicle. A main base 603 is mounted on the vehiclefloor F via the longitudinal slide rails 602 to permit longitudinalmovement. A rotary disc 604 has an outer ring 604 a and an inner ring604 b and is mounted on the upper surface of the main base 603. A pairof lateral slide rails 606 are mounted on the upper surface of the innerring 604 b via a sub base 605. A swing base 607 is mounted on thelateral slide rails 606 to permit sliding movement within a limitedrange via the lateral slide rails 606.

When the seat body 610 is rotated to the door opening side by the rotarydisc 604 as shown in FIG. 55, the lateral slide rails 606 are alsodirected to the door opening side. In this state, the seat body 610 canslide to the exterior side (“lateral slide”).

Designated by numeral 606 a are guide rollers rotatably mounted in fourpositions on the front and rear portions of both sides of the swing base607. When the guide rollers 607 roll within and along the interior ofthe lateral slide rails 606 having a generally U-shaped cross section,the swing base 607 slides within the limited range.

A seat holder 609 is mounted on the swing base 607 via a pair of rightand left quadric link mechanisms 608 (a pair in the directionperpendicular to the plane of the drawing as viewed in FIG. 55). Twolink arms 608 a,608 b of each of the quadric link mechanisms 608 arerotatably connected to the swing base 607 and the seat holder 609 byshaft 608 c,608 d,608 e,608 f. The seat body 610 is mounted on the seatholder 609.

When an electric cylinder mounted on the swing base 607 is actuated as adriving source to rotate a driving arm 608 g that is secured to the rearshaft 608 d, the quadric link mechanisms 608 pivot in the lateraldirection of the vehicle (in the right-left direction as viewed in FIG.55). The electric cylinder essentially consists of an electric motor608M and a ball screw and does not require any particular modificationto achieve this embodiment (cf. the driving system of the firstembodiment). In FIG. 55, the back of the electric motor 608M is shown.

The above-described sliding movements in the longitudinal and lateraldirections of the vehicle are performed manually by users. However, suchsliding movements may be electrically powered by an electric motor as adriving source. The longitudinal and lateral sliding movements can belocked on the front and rear ends in the sliding direction or in anyposition between the front and rear ends by means of a longitudinalslide lock mechanism and a lateral slide lock mechanism, respectively.Further, the rotational movement by the rotary disc 604 can be locked toprevent rotation in the positions of the seat body 610 facing the frontof the vehicle and to the door opening side (rotation lock mechanism).In these points, any particular modifications are not necessary.

With the above-described construction, after the seat body 610 has beendirected to the door opening side and locked to prevent rotation, theseat body 610 is manually moved from the rear most position in thelateral sliding movement, which is shown by a solid line in the drawing,to the front position, which is shown by a broken line in the drawing.The lateral sliding movement is locked in the front position.Thereafter, when the electric cylinder is actuated, the quadric linkmechanisms 608 pivot to the exterior side, so that the seat body 610 isalso extended to the exterior side position shown by the broken line.

In order to return the seat body 610 from this extended position, theelectric cylinder is rotated in the reverse direction to move the seatbody 610 back to the front position of the lateral sliding movement.Thereafter, the lateral slide lock mechanism is unlocked and the seatbody 610 is manually moved back to the rearmost position in the lateralsliding movement. The lateral slide lock mechanism is locked in therearmost position. After the seat body 610 has thus been moved back tothe rearmost position in the lateral sliding movement, the rotation lockmechanism is unlocked and the seat body 610 is rotated by about 90° tothe position facing the front of the vehicle. In this position, therotational movement is locked. Thereafter, the main base 603 and thusthe seat body 610 are returned to the rearmost position of thelongitudinal sliding movement and then locked in position. Thus, theentry of the passenger into the vehicle is completed. On the other hand,by reversing the above-described procedure, the passenger can get out ofthe vehicle to the outside while sitting in the seat body 610. Thus, thepassenger can get into a predetermined position in the vehiclecompartment and can also get out of the vehicle, while sitting in theseat body 610, so that the passenger can easily enter and exit thevehicle.

In the rotating vehicle seat 601 thus constructed, a swing lockmechanism 620 is provided between the seat holder 609 and the swing base607 and serves to lock the swinging movement of the seat body 610 whenthe vehicle is abruptly decelerated. The rotating vehicle seat 601according to this embodiment features the swing lock mechanism 620, andmore specifically, that the swinging movement of the seat body 610 islocked irrespective of the sliding position of the lateral slide rails606.

The swing lock mechanism 620 is shown in detail in FIG. 56. A lock plate621 is mounted to the underside of the side edge of the seat holder 609.A lock recess 621 a is formed in the front edge of the lock plate 621.An auxiliary strip plate 622 is attached on the outside surface of thelock plate 621. An operating pin 623 is mounted on and extends laterallyoutwardly from the lower portion of the outside surface of the auxiliaryplate 622. The position of the auxiliary plate 622 can be adjustedvertically.

A lock holder 625 is mounted on the side surface of the swing base 607for vertical pivotal movement around a pivot 626. The lock holder 625 isformed by fixing two plates 625 a in parallel to each other with apredetermined spacing therebetween by the pivot 626. A torsion spring628 is disposed around the pivot 626 between the plates 625 a. Althoughit is not shown, one end of the torsion spring 628 is fixed to one ofthe plates 625 a. The other end of the torsion spring 628 is bent into agenerally L-shape to form a free end 628 a that is not fixed to anycomponents. The torsion spring 628 has a function of imparting upwardrotational force to the lock holder 625, which will be described indetail below.

A lock pin 627 extends across and is fixed to the distal ends of theplates 625 a. When the lock pin 627 is engaged in the lock recess 621 aof the lock plate 621, the seat body 610 is locked to prevent swingingmovement.

A stopper plate 629 is mounted on and extends laterally outwardly fromthe side surface of the swing base 607 below the lock holder 625, andserves to limit the downward pivotal end of the lock holder 625. Whenthe lock holder 625 pivots until it contacts the stopper plate 629, thelock holder 625 lies generally horizontally. At this time, the lock pin627 is completely out of the travelling path of the lock plate 621, thuspermitting the seat body 610 to be extended.

In FIGS. 55 to 57, a solid line depicts the seat body which is locked toprevent swinging movement. In this locked state, the quadric linkmechanisms 608 are in the most raised position, and thus, the seatholder 609 is positioned furthest to the interior side (to the right asviewed in FIG. 55) with respect to the swing base 607. In such a swinglocked state, the lock pin 627 is substantially engaged in the lockrecess 621 a of the lock plate 621. Further, the free end 628 a of thetorsion spring 628 is pressed by the rear edge of the auxiliary plate622. Thus, the torsion spring 628 provides a biasing force, and the lockholder 625 is pivoted around the shaft 626 toward the raised position bythe biasing force. As a result, as described above, the lock pin 627 isengaged in the lock recess 621 a of the lock plate 621. Further, in thislocked state, the operating pin 623 is in contact with the upper edge ofthe outside plate 625 a of the lock holder 625.

In the swing locked state, when the electric cylinder is actuated tostart the swinging movement, the swing lock mechanism 620 is unlocked asshown in FIGS. 57 to 59. When the electric cylinder is actuated, theseat holder 609 and the seat body 610 start to move horizontally to theexterior side with the movement of the quadric link mechanisms 608. Atthis time, as shown in FIG. 58, the lock plate 621 also moves likewise.As described above, the operating pin 623 is mounted on the auxiliaryplate 622 of the lock plate 621 and is held in contact with the upperedge of the outside plate 625 a of the lock holder 625. Further, at thistime, the lock holder 625 is held in the generally raised position bythe biasing force of the torsion spring 628. Therefore, when the lockplate 621 starts to move in the generally horizontal direction, the lockholder 625 is pressed by the operating pin 623 to thereby start torotate downward. The timing when the lock holder 625 starts to pivotdownward with the movement of the lock plate 621 must be set such thatthe lock plate 621 does not interfere with the lock pin 627. Such timingcan be properly set by adjusting the vertical position of the auxiliaryplate 622.

Further, at this time, the free end 628 a of the torsion spring 628 isstill pressed against the auxiliary plate 622. Thus, the biasing forceof the torsion spring 628 acts on the lock holder 625. Therefore, themovement of the operating pin 623 causes the lock holder 625 to pivotdownward against the biasing force of the torsion spring 628.

As the lock holder 625 pivots downward, the lock pin 627 is graduallydisengaged from the lock recess 621 a of the lock plate 621. When thelock plate 621 further moves to the exterior side while the lock pin 627is gradually disengaged from the lock recess 621 a, the pressing forceof the auxiliary plate 622 pressing the free end 628 a of the torsionspring 628 is reduced, and thus the biasing force of the torsion spring628 is gradually reduced.

When the lock holder 625 is further pivoted downward to a generallyhorizontal position as shown in FIG. 58, the pressing force of theauxiliary plate 622 against the free end 628 a of the torsion spring 628is not substantially applied. Further, the pressing force of theoperating pin 623 against the plate 625 a is not substantially applied.Therefore, the lock holder 625 will then pivot downward under its ownweight until it contacts the stopper plate 629. Thus, the lock plate 621is completely out of the travelling path of the lock plate 621 (in theunlocked state). After the lock plate 621 has thus been disengaged fromthe lock holder 625, the electric cylinder is further rotated to movethe quadric link mechanisms 608 to the extended position. As a result,the seat body 610 is moved to the outside of the vehicle along apredetermined path. The swing lock mechanism 620 in this stage is shownin FIG. 59.

On the other hand, by reversing the above-described procedure, the seatbody 610 can be returned from the outside extended position to theinside of the vehicle. Specifically, when the electric cylinder isrotated in the reverse direction, the quadric link mechanisms 608 moveto the raised position, and thus the seat body 610 and the seat holder609 are moved along the same path back to the interior side. As shown inFIG. 59, in the unlocked state in which the lock plate 621 is away fromthe lock holder 625, the lock holder 625 is held in contact with thestopper plate 629 under its own weight and in a generally horizontalposition. In this state, the free end 628 a of the torsion spring 628does not contact any components, and thus the spring 628 does not exertany biasing force.

As shown in FIG. 58, when the seat body 610 is returned generally abovethe swing base 607, the lock plate 621 is returned above the lock holder625, and the rear edge of the auxiliary plate 622 contacts the free end628 a of the torsion spring 628. In this state of contact, when the seatbody 610 is further moved toward the interior side, the free end 628 aof the torsion spring 628 is pressed rearward (toward the interiorside). Therefore, the torsion spring 628 provides the biasing force torotate the lock holder 625 to the raised position. The biasing force isgradually increased as the auxiliary plate 622 moves toward the interiorside.

In this stage, however, the front of the lock plate 621 has not yetpassed over the lock pin 627 rearward (to the right as viewed in thedrawing) with respect to the lock pin 627. Therefore, the lock holder625 still must be held in the generally horizontal position. To thisend, in this embodiment, in the stage in which the biasing force of thetorsion spring 628 begins to be exerted, the operating pin 623 on theauxiliary plate 622 again contacts the upper edge of the lock holder625. As shown in FIG. 58, the contact position is set to be located onthe left of the shaft 626 (the center of rotation) of the lock holder625 in the beginning of contact, so that the lock holder 625 isprevented from rotating toward the raised position. Therefore, in thisstage, the lock holder 625 is still held in a generally horizontalposition, and only the biasing force of the torsion spring 628 graduallyincreases.

Subsequently, when the quadric link mechanisms 608 are returned to thegenerally raised position and the seat body 610 is returned to thegenerally original position, the front end of the lock plate 621completely passes above the lock pin 627 and the operating pin 623passes above the shaft 626 of the lock holder 625. As a result, the lockholder 625 is permitted to rotate toward the raised position. The timingwhen the lock holder 625 starts to rotate together with the movement ofthe lock plate 621 is properly set by adjusting the vertical position ofthe auxiliary plate 622 or by properly setting the position of the shaft626.

The operating pin 623 has a function of limiting the rotation of thelock holder 625 toward the raised position (in the swing lockingdirection) in the process of returning the seat body 610 to the insideof the vehicle. On the other hand, the operating pin 623 has anotherfunction of rotating the lock holder 625 downward (in the unlockingdirection) in-the process of extending the seat body 610 to the outsideof the vehicle.

When the lock holder 625 is thus permitted to rotate toward the raisedposition, the free end 628 a of the torsion spring 628 is sufficientlybiased by the auxiliary plate 622, so that the biasing force increasesenough to rotate the lock holder 625 to the raised position. Therefore,at this time, the lock holder 625 is rotated to the raised position, andthe lock pin 627 is engaged in the lock recess 621 a of the lock plate621. Thus, the swing lock mechanism 620 is locked.

When the quadric link mechanisms 608 are returned all the way to theraised position and the seat body 610 is returned above the swing base607, the swinging movement is completed and the electric cylinder isstopped. In this swing lock state, the free end 628 a of the torsionspring 628 is pressed by the auxiliary plate 622, so that the lockholder 625 is still biased toward the raised position by the biasingforce of the torsion spring 628. Therefore, the lock pin 627 is heldwithin the lock recess 621 a of the lock plate 621, and thus, the swinglocked state is maintained.

The “swing locked state” in this embodiment refers to the state in whichthe seat body 610 can be prevented from swinging in the event of abruptdeceleration of the vehicle, and more specifically, to the state inwhich lock holder 625 is moved to the raised position and the lock pin627 is held within the lock recess 621 a of the lock plate 621.Therefore, even in this swing locked state, swinging movement which isinvolved in the normal entry/exit operations during stop of the vehicle,is not limited at all. Therefore, the user can swing the seat body 610without a special unlocking operation.

In the event of abrupt deceleration of the vehicle when the vehicle isrunning, a large gravity G (acceleration of gravity) is exerted on theseat body 610. In this case, while the front portion of the vehiclesinks, inertial force of displacing the front portion of the vehiclerelatively upwardly, is applied to the seat body 610 by elasticdeformation of the quadric link mechanisms 608 or other factors. At thistime, the force of the operating pin 623 pressing the lock holder 625 isgreatly reduced. As a result, the lock plate 621 is engaged with thelock pin 627 of the lock holder 625, so that the swinging movement ofthe seat body 610 is mechanically locked.

As described above, with the rotating vehicle seat 601 according to thisembodiment, when the extending movement of the seat body 610 to theexterior side is started, the swing lock mechanism 620 is unlockedsimultaneously. On the other hand, when the seat body 610 is returned tothe interior side, the swing lock mechanism 620 is automatically lockedin the final stage. The lock plate 621 for achieving the swing lock isprovided on the seat holder 609, and the lock holder 625 is provided onthe swing base 607.

Thus, with the rotating vehicle seat 601 according to this embodiment,the swinging movement is locked and unlocked irrespective of the lateralsliding position. Therefore, the swinging movement of the seat body 610is locked by the swing lock mechanism 620 in the front end lateralsliding position as well. The problem of the known rotating seat doesnot occur in which the swinging movement is unlocked in any positionother than the rear end lateral sliding position.

With this construction, the lateral slide rails 606 can be utilized aslongitudinal slide rails. Specifically, when the seat body 610 is in theposition facing the front of the vehicle (the normal seated position),the position of the seat body 610 in the longitudinal direction of thevehicle can be adjusted by the lateral slide rails 606 as well as thelongitudinal slide rails 602.

For example, in a vehicle, such as a van, in which the front seat floorFH (on which a driver's seat and a passenger's seat are installed) isset at a higher lever than the rear seat floor FL (on which rear seatsare installed) as shown in FIG. 60, the rotating vehicle seat 601 can bemoved from the rear seat floor FL substantially to the passenger's seaton the front seat floor FH, if the passenger's seat on the front seatfloor FH is removed.

Specifically, the seat body 610 cannot be moved to the passenger's seaton the front seat floor FH only by means of the longitudinal slide rails602, because a step exists between the rear seat floor FL and the frontseat floor FH. As described above, the lateral slide rails 606 arelocated at a position higher than the longitudinal slide rails 602.Therefore, when the longitudinal slide rails 602 are used for thelongitudinal sliding movement of the seat body 610 on the rear seatfloor FL, and the lateral slide rails 606 are used at the front end ofthe rear seat floor FL to further move the seat body 610 forward withrespect to the vehicle, the seat body 610 can be moved onto the frontseat floor FH.

When the rotating vehicle seat 601 is moved into the vehicle through thedoor opening to the side of the rear seat floor FL and then moved to thepassenger's seat as described above, the passenger (for example, ahandicapped person) can sit alongside the driver. Therefore, thepassenger can sit more comfortably without having an awkward feeling (bybeing specially handled and treated differently by being required to sitin the rear seat).

Thus, with the rotating vehicle seat 601 according to this embodiment,the swing lock mechanism 620 functions irrespective of the slidingposition, so that the lateral slide mechanism can be utilized as alongitudinal slide mechanism. Therefore, as described above, thelongitudinal sliding movement of the rotating vehicle seat 601 can beextended to the front seat floor FH, so that the variety of theapplication styles (seat variations) can be increased.

Further, the swing lock mechanism 620 in this embodiment is notconstructed to utilize the sliding movement by means of the slide rails606. Therefore, the swing lock mechanism 620 can be easily applied toother seats that do not have the lateral slide mechanism.

Further, the swing lock mechanism 620 in this embodiment is constructedto provide swing lock and unlock using a fully mechanical system andwithout using an actuator, such as an electric motor or a cylinder.Therefore, without the need for a power source or an air source andwithout the need for installation of electric wiring or air piping, easeof assembling and excellent maintainability can be obtained. Further,reliable locking and unlocking operations can be maintained for a longerperiod of time.

Further, by properly determining the thickness of the auxiliary plate622 or the diameter of the operating pin 623 such that the auxiliaryplate 622 or the operating pin 623 has a lower impact resisting strengththan the other components, the auxiliary plate 622 or the operating pin623 can be set so as to break when an external impact force exceeding apredetermined value is applied on the slide lock mechanism 260. As aresult, even if the lock plate 621 is momentarily displaced forward ofthe vehicle together with the seat body 610, the auxiliary plate 622 orthe operating pin 623 breaks and can no longer press (rotate in theunlocking direction) the lock holder 625. As a result, the slide lockmechanism 260 can be maintained in the locked state. With thisconstruction, even if a large acceleration G (acceleration of gravity)is exerted on the passenger or the rotating vehicle seat 601, the swinglocked state is reliably maintained, so that the safety of the passengercan be secured.

Various changes or modifications may be added to the above-describedseventh embodiment. For example, while the torsion spring 628 has beendescribed as being used as means for imparting the biasing force torotate the lock holder 625 to the raised position, a plate spring 631may be used instead of the torsion spring 628. A swing lock mechanism620 using a plate spring 631 is shown in FIG. 61. In this construction,the lower end of the plate spring 631 is secured to the rear end surfaceof the lock holder 632. The plate spring 631 extends upward to the backof the lock plate 621. In this example, as shown in the drawing, a freeend 631 a of the plate spring 631 contacts the rear end of the lockplate 621. The remaining construction of the lock holder 632 is the sameas the seventh embodiment. Further, like the seventh embodiment, theauxiliary plate 622 is mounted on the lock plate 621, and the operatingpin 623 is mounted on the auxiliary plate 622. The operation of theoperating pin 623 is the same as the seventh embodiment. The same effectas the seventh embodiment can be obtained with this swing lock mechanism30.

An embodiment of the invention as described in claim 10 (an eighthembodiment) will now be explained with reference to FIGS. 62 to 68.

In a swing-down type rotating vehicle seat in which the seat body ismounted to permit swinging movement to the outside of the vehiclethrough the door opening by the quadric link mechanisms, it is necessaryto lock all operating mechanisms at least when the vehicle is running(in the state in which the passenger is sitting facing the front ofvehicle). To this end, a rotating vehicle seat of this type is providedwith a swing lock mechanism for locking the swinging movement.

However, in a known swing lock mechanism, locking and unlockingoperations are performed manually. Such operations are troublesome, andin this respect, the usability of this type of the rotating vehicle seatis impaired. It is, accordingly, an object of the invention as describedin claim 10 to provide a rotating vehicle seat which includes a swinglock mechanism that can automatically lock and unlock the swingingmovement of the seat body without the need for special operations by theuser.

As shown in FIG. 62, in the eighth embodiment, a rotating vehicle seat701 will be described. The rotating vehicle seat 701 is set on the leftside of the vehicle, and the door opening D is provided on the left ofthe rotating vehicle seat 701. When a seat body 710 is rotated by about90° to the left from the position facing the front of the vehicle, whichis shown by a solid line in the drawing, the seat body 710 is moved tothe position facing the door opening D, which is shown by a broken line.In this state, the seat body 710 can be moved to the outside of thevehicle through the door opening D.

The rotating vehicle seat 701 is shown in detail in FIG. 63. Therotating vehicle seat 701 is shown in the position facing the front ofthe vehicle in FIG. 63.

The basic components of the rotating vehicle seat 701 do not require anyparticular modifications in this embodiment as compared with each of theforegoing embodiments, but will now be briefly explained. Designated bynumeral 702 is a pair of parallel longitudinal slide rails mounted onthe vehicle floor F and extending in the longitudinal direction of thevehicle. A main base 703 is mounted on the vehicle floor F via thelongitudinal slide rails 702 to permit longitudinal movement. A rotarydisc 704 has an outer ring 704 a and an inner ring 704 b and is mountedon the upper surface of the main base 703. The rotary disc 704 ismounted in a position displaced from the center to the exterior side onthe main base 703 (a position displaced toward this side of the plane ofFIG. 63) (see FIG. 64).

A swing base 707 is mounted on the upper surface of the inner ring 704 bof the rotary disc 704. A seat holder 709 is mounted above the swingbase 707 via a pair of right and left quadric link mechanisms 708 (apair in the direction perpendicular to the plane of the drawing asviewed in FIG. 63). Two link arms 708 a,708 b of each of the quadriclink mechanisms 708 are rotatably connected to the swing base 707 andthe seat holder 709 by pivots 708 c,708 d,708 e,708 f. The seat body 710is mounted on the seat holder 709.

When an electric cylinder (not shown) mounted on the swing base 707 isactuated as a driving source to rotate a driving arm that is secured tothe rear shaft 708 d, the quadric link mechanisms 708 pivot in thelateral direction of the vehicle (in the right-left direction as view inFIG. 63). The electric cylinder as a driving source essentially consistsof an electric motor and a ball screw and does not require anyparticular modification to achieve this embodiment.

The sliding movement of the seat body 710 in the longitudinal directionof the vehicle is performed manually by users. However, the slidingmovement may be electrically powered by an electric motor as a drivingsource. The longitudinal sliding movement can be locked on the front andrear ends in the sliding direction or in any position between the frontand rear ends by means of a lock mechanism. Further, the rotationalmovement by the rotary disc 704 can be locked against rotation in thepositions of the seat body 710 facing the front of the vehicle and tothe door opening D. In these points, no particular modifications arenecessary.

With the above-described construction, when the seat body 710 is rotatedand directed to the door opening D, and in this state, the electriccylinder is actuated to rotate the quadric link mechanisms 708 to theexterior side, the seat body 710 can be extended to the exterior sideposition through the door opening D. Thus, the passenger can get out ofthe vehicle while sitting in the seat body 710.

In order to return the seat body 710 into the vehicle, the electriccylinder is rotated in the reverse direction to move the quadric linkmechanisms 708 to the raised position, and thereafter, the seat body 710is rotated by about 90° from the position facing the front of thevehicle and then moved rearward with respect to the vehicle. Thus, theentry of the passenger into the vehicle is completed. Therefore, thepassenger can get into a predetermined position in the vehiclecompartment and can also get out of the vehicle while sitting in theseat body 710, so that the passenger can easily get into and out of thevehicle.

In the rotating vehicle seat 701 thus constructed, a swing lockmechanism 720 is provided between the seat holder 709 and the swing base707 and serves to lock the swinging movement of the seat body 710. Therotating vehicle seat 701 according to this embodiment features theswing lock mechanism 720. The swing lock mechanism 720 will now bedescribed in further detail.

The swing lock mechanism 720 is shown in detail in FIGS. 64 to 66. Alock plate 721 is mounted to the underside of the right end portion ofthe seat holder 709. A lock recess 721 a is formed in the front edge ofthe lock plate 621. A lock pin 722 a of a lock holder 722 is engaged inthe lock recess 721 a of the lock plate 721, as will be described indetail below, and thus the seat body 710 is locked to prevent swingingmovement.

The lock holder 722 is mounted on the right side portion of the swingbase 707 for vertical pivotal movement around a pivot 723. The pivot 723(the center of rotation of the lock holder 722) is located near the rearcorner of the lock holder 722. A tension spring 725 (which is not shownin FIG. 64) is disposed between the lock holder 722 and the swing base707. The lock holder 722 is biased downward by the tension spring 725.

When the lock holder 722 pivots upward around the pivot 723 against thetension spring 725, the lock pin 722 a on the distal end of the lockholder 722 is engaged in the lock recess 721 a of the lock plate 721.Thus, the seat body 710 is locked to prevent swinging movement.

An anchor hook 724 is mounted on the main base 703 that rotatablysupports the swing base 707, and the anchor hook 724 is located near theend of the main base 703 and more to the interior side than the rotarydisc 704 on the main base 703. The anchor hook 724 extends raised intothe travelling path of the lock holder 722 that pivots together with therotation of the swing base 707. The anchor hook 724 serves to couple thevertical pivotal movement of the lock holder 722 to the rotationalmovement of the swing base 707. Specifically, when the seat body 710 islocated in the position facing the front of the vehicle, a positionadjusting plate 722 b that is mounted on the lower front corner portionof the lock holder 722, contacts a distal end portion 724 a of theanchor hook 724. In this contact state, when the seat body 710 isfurther rotated, the lower front corner portion of the lock holder 722is pushed upward via the position adjusting plate 722 b, so that thelock holder 722 pivots upward around the pivot 723. The timing when thelock holder 722 pivots can be adjusted by adjusting the position of theposition adjusting plate 722 b.

On the other hand, when the seat body 710 is rotated to the door openingside, the lower front corner portion (the position adjusting plate 722b) of the lock holder 722 is disengaged from the distal end portion 724a of the anchor hook 724. As a result, the lock holder 722 is permittedto pivot downward. Thus, the lock holder 722 pivots downward under itsown weight and by the biasing force of the tension spring 725. When thelock holder 722 pivots downward around the pivot 723, the lock pin 722 ais disengaged from the lock recess 721 a of the lock plate 721, and thusthe swing lock of the seat body 710 is released.

A generally U-shaped recess 724 b is formed in the front end of theanchor hook 724. When the seat body 710 is located in the positionfacing the front of the vehicle, as shown in FIGS. 64 and 65, a rear endportion 707 a of the swing base 707 is engaged into the recess 724 b ofthe anchor hook 724. With this construction, the swing base 707 and thusthe seat body 710 are prevented from excessive rotation in the directionopposite to the door opening D.

With the rotating vehicle seat 701 of this embodiment, when the seatbody 710 is rotated, the swing lock mechanism 720 is locked or unlockedby coupling with the rotation of the seat body 710. Therefore, unlikeknown rotating seats, the users do not need to manually operate theswing lock mechanism, so that the usability of the rotating vehicle seatcan be improved.

Particularly, with the rotating vehicle seat 701 of this embodiment,when the position adjusting plate 722 b on the lower front cornerportion of the lock holder 722 is pushed up by contact with the distalend portion 724 a of the anchor hook 724, the lock holder 722 rotatesupward and is held in the locked position. However, if it isconstructed, for example, such that a biasing force of a spring is usedto rotate the lock holder to the locked position and to hold it in thelocked position, in the event of a collision from behind or duringdriving on a bad road, the lock holder may be rotated to the unlockedposition against the biasing force of the spring by the impact (inertialforce) generated by the collision from behind or by vibrations generatedby driving on a bad road. As a result, the seat body 710 may be extendedforward with respect to the vehicle. In this respect, with theconstruction of this embodiment, as long as the seat body 710 is held inthe position facing the front of the vehicle by a separately providedrotation lock mechanism, the lock holder 722 is pushed up by the anchorhook 724 and mechanically held in the swing locked position. Therefore,even in the event of occurrences generating a big impact or vibrations,the seat body 710 can be reliably maintained in the swing locked state.

Further, when the seat body 710 is located in the position facing thefront of the vehicle, the rear end portion 707 a of the swing base 707is engaged in the recess 724 b of the anchor hook 724, so that the seatbody 710 is prevented from excessive rotation.

The normal range of rotating the seat body 710 in the entry and exit ofpassengers (normal rotational range) is about 90° between the positionfacing the front of the vehicle and the position facing the door openingD. By engaging the rear end portion 707 a of the swing base 707 with therecess 724 b of the anchor hook 724, the seat body 710 is prevented fromexcessive rotation beyond this normal rotational range, that is, fromrotating further to the interior side from the position facing the frontof the vehicle.

As shown in FIG. 67, when the center of rotation C of the seat body 710(the position of the rotary disc 704) is displaced to the exterior sidewith respect to the center of gravity G of the seat body 710 (includingthe seat holder 709 and the swing base 707; the center of gravity Gbeing the same throughout this specification), if the vehicle issubjected to a strong impact from behind, by a collision from behind orsimilar causes, the seat body 710 is subjected to a force in a directionof rotating the seat body 710 to the interior side, as shown by an arrowin FIG. 67, by the positional relationship between the center ofrotation C and the center of gravity G.

However, with the above-described structure for preventing excessiverotation, as shown in FIG. 68, the anchor hook 724 engages the rear endportion 707 a of the swing base 707 on the end of the interior side (theend of the upper side as viewed in the drawing), thus preventing theswing base 707 from rotating clockwise in the drawing. Therefore, in theevent of a collision from behind, as described above, the seat body 710can be reliably held in a predetermined position (facing the front ofthe vehicle). The rotational position of the seat body 710 is retainedby a separately provided rotation lock mechanism, but can be furtherreliably retained by this mechanism to prevent excessive rotation.

Further, because the rear end portion 707 a of the swing base 707 isengaged in the recess 724 b of the anchor hook 724 when the seat body710 is located in the position facing the front of the vehicle, a strongupward force (a force in the direction of raising the seat body 710)that will be applied to the swing base 707 through the seat belt canalso be received by the anchor hook 724. Consequently, the rigidity ofthe seat body 701 against the so-called seat sled load (a strong impactload applied through the seat belt in the event of a forward collision)can be enhanced.

Various changes or modifications may be added to the above-describedembodiment. For example, although in this embodiment, the rotating seathas been described as being installed on the left side in the vehicle,the swing lock mechanism of this embodiment can be also applied to therotating seat installed on the right side.

Further, although the lock holder 722 has been described as beingreturned to the unlocking direction under its own weight or by thetension spring 725, a torsion spring or a compression spring may be usedinstead of the tension spring 725.

Further, although excessive rotation of the seat body 710 has beendescribed as being prevented by engagement between the anchor hook 724and the rear end portion 707 a of the swing base 707, if a normallyprovided rotation lock mechanism can sufficiently prevent the excessiverotation, the anchor hook 724 as means for preventing the excessiverotation may be omitted.

An embodiment (a ninth embodiment) of the invention as described inclaims 11 and 12 will now be explained with reference to FIGS. 69 to 75.

A seat sliding mechanism 891 of a rotating vehicle seat 890 is shown inFIGS. 73 to 75. The rotating vehicle seat 890 is applied to apassenger's seat next to a driver's seat. A seat stand 893 is installedon a vehicle floor 892 in a predetermined position, and a rotary disc894 is mounted on the seat stand 893. A pair of right and left parallelseat slide rails 895 are mounted on the rotary disc 894 with apredetermined spacing therebetween and each of the rails 895 has apredetermined length and has a slide groove 896. A base 897 is mountedon the seat slide rails 895 via slide members (not shown) to permitlongitudinal movement along the seat slide rails 895.

The lower ends of a pair of quadric link arms 898,899 are pivotallyconnected to the rear portions of both sides of the base 897, andgenerally L-shaped right and left extending arms 860 are pivotallyconnected to the upper ends of the quadric link arms 898,899. Areinforcing frame extends across horizontal portions 861 of theextending arms 860, and a seat body 862 is mounted on the horizontalportions 861. A swing lock mechanism 863 and a stopper mechanism 864 areremovably disposed between the base 897 and the underside of thehorizontal portions 861.

The seat body 862 is directed to the front of the vehicle in the stateshown in FIG. 73, and the seat slide rails 895 also extendlongitudinally with respect to the vehicle. In this state, as shown inFIG. 74, four hook brackets 865 are mounted below the seat slide rails895 and on the floor 892 in predetermined locations around the seatstand 893. Each of the hook brackets 865 has a generally U-shaped crosssection. As shown in FIG. 75, a cushion 866 is provided on and under anupper portion of the hook brackets 865. A front hook 867 and a rear hook868 are mounted to each of the right and left seat slide rails 895 andengage with the hook brackets 865. Further, a seat belt anchor 870 of aseat belt 869 is mounted, for example, on the seat body 862 or theextending arm 860.

The rotating vehicle seat 890 thus constructed is directed to the dooropening side by rotating the seat slide rails 895 to the door openingside via the rotary disc 894.

At the same time, the hooks 867,868 are disengaged from the hookbrackets 865. In this state, when the base 897 is moved forward of theseat, the swing lock mechanism 863 is disengaged from the stoppermechanism 864, and thus the claw portion mounted to the underside of thehorizontal portion 861 is disengaged. Thereafter, when an actuator (notshown) of the quadric link arms 898,899 is actuated, the seat body 862is extended to the outside via the extending arms 860. At the same time,the seat body 862 is swung down to a predetermined vertical positionabove the road surface, so that the passenger can change, for example,to a wheelchair. On the other hand, the seat body 862 is returned to anoriginal position inside the vehicle by reversing the above procedures.

However, the seat slide rails 895, which form a seat sliding mechanism891 of the rotating vehicle seat 890, are mounted on the upper surfaceof the rotary disc 894. Further, the front and rear hooks 867,868mounted to the seat slide rails 895 engage the hook brackets 865 mountedon the floor 892 when the seat body 862 is directed to the positionfacing the front of the vehicle. Thus, it is constructed such that theimpact load transmitted from the seat belt 869 is allowed to escape tothe floor 892. Therefore, during rotation of the seat body 862, thefront and rear hooks 867,868 interfere with the cushions 866 of the hookbrackets 865 and the cushions 866 may be removed. As a result, therotating operation is deteriorated. Further, the number of components isincreased in order to absorb the impact load transmitted from the seatbelt, thus resulting in cost increase. The invention as described inclaim 11 or 12 has been made in view of the above-noted problems, andits object is to provide a seat sliding mechanism that can stabilize thelongitudinal sliding movement of the seat body by a simple constructionand can absorb the impact load from the seat belt.

In the ninth embodiment which will now be explained, the same points asthe foregoing embodiments will not be described. As shown in FIG. 70, aV-shaped groove 811 a is formed on the outer side surface of each of twoinner rails 811 on the rotating support base as shown in FIG. 69. Twoparallel outer rails 832 are mounted on and extend along both sides of abase 831 of the longitudinal support base with a predetermined spacingtherebetween. The outer rails 832 are disposed on and along the outerside of the inner rails 811. A V-shaped groove 832 a, which is similarto the groove 811 a, is also formed in each of the outer rails 832 onthe side surface facing the inner rails 811. The groove 832 a isdisposed facing the groove 811 a. A plurality of steel balls 833 (orrolling elements) are fitted into the grooves 811 a, 832 a between theinner rails 811 and the outer rails 832, to thereby form a pair of leftand right linear guide mechanisms 834. Further, a guard rail 837 havinga generally L-shaped cross section is mounted on the base 831 andextends a predetermined length along and on the inner side of each ofthe inner rails 811. The guard rails 837 serve to support the innerrails 811 in a manner that permits the inner rails 811 to slide and isprevented from being disengaged from the outer rails 832. By providingthe guard rails 837 in addition to the linear guide mechanisms 834, therotating support base and thus the lift-up mechanism and the seat body802 can be more smoothly moved in the longitudinal direction of thevehicle without rattling. Although it is not shown, the base 831 of thelongitudinal support base is secured to the vehicle floor by bolts.Thus, the rotating seat is installed in a predetermined position (theposition of a passenger's seat). Although steel balls 833 have beendescribed as the rolling elements, a cylindrical roller, for example,may be used.

Further, as shown in FIGS. 71 and 72, when the rotating vehicle seat isin the slide locked state in the rear end position of the longitudinalsliding range (in the state in which the cylindrical portion 83 a isinserted into the lock hole 31 a in FIG. 9), extending portions 811 b ofthe inner rails 811 on the rear end extend rearward by a predeterminedlength. A generally inverted U-shaped hook 839 is disposed on thevehicle floor side on the travelling path of each of the extendingportions 811 b, and the extending portion 811 b is removably insertedthrough the hook 839.

With the rotating vehicle seat thus constructed according to the ninthembodiment, the inner rails 811 on which the rotary disc 813 of therotating support base is mounted can be moved longitudinally via theplurality of steel balls 833 disposed between the outer rails 832, whichare mounted on the base 831 of the longitudinal support base, and theinner rails 811. Further, the extending portions 811 b of apredetermined length extend on the rear end of the inner rails 811 andarc removably inserted through the hooks 839 that are disposed on thevehicle floor side. Therefore, when the seat body 2 is in the interiorside position W0 (in the state shown in FIG. 11(A)), the extendingportions 811 b of the inner rails 811 are inserted through the hooks839. Thus, the inner rails 811 can be prevented from being raised by abelt load that will act on the seat belt in the event of hard braking orcollision when the vehicle is running. Further, the belt load can betransferred from the hooks 839 to the floor side, so damage to thelinear guide mechanism 834 can be prevented.

Further, because the guard rail 837 is provided on the base 831 on andalong the inner side of the inner rails 811 and extends in parallel tothe outer rails 832, the deformation of the inner rails 811 can beminimized and removal of the steel balls 833 can be prevented, so thatthe longitudinal movement of the linear guide mechanism 834 can bemaintained with stability.

An embodiment (a tenth embodiment) of the invention as described inclaim 13 will now be explained with reference to FIGS. 76 to 82. Thesame components as the first embodiment will be identified by the samenumerals. A rotating vehicle seat 950 is constructed to couple thelongitudinal sliding movement of a seat body 902 and the rotationalmovement of the seat body 902 to the door opening D. The rotatingvehicle seat 950 includes a rotating support base 910 that slideslongitudinally with respect to the vehicle via slide rails 932 mountedon the vehicle floor as shown in FIG. 81, and the seat body 902 thatrotates via a rotary disc 913 mounted on the rotating support base 910.A rotation/slide coupling mechanism 905 includes a rack 955 mounted onthe vehicle floor side, an intermediate gear 956 mounted on the rotatingsupport base 910, and a circular-arc pinion gear 957 mounted on the sideof the seat body 902.

The intermediate gear 956 always engages the rack 955. When the seatbody 902 rotates by a predetermined angle α to the exterior side, thepinion gear 957 starts to engage the intermediate gear 956. As shown inFIG. 81, the pinion gear 957 has a circular-arc shape extending in arange of about 90° and no engagement teeth are provided within apredetermined angular range α on the initial engagement side (the end inthe counterclockwise direction). Therefore, the pinion gear 957 does notengage the intermediate gear 956 within the initial range of about theangle of α at the beginning of rotation, in which the seat body 902 isrotated from the initial seated position (the position facing the frontof the vehicle, as shown by a solid line in FIG. 81) to the door openingside (in the counterclockwise direction). Thus, the seat body 902 onlyrotates without moving forward (in the “non-coupling range”).

When the seat body 902 is rotated by the angle α to the door openingside, the pinion gear 957 starts to engage the intermediate gear 956.Thereafter, the seat body 902 moves forward with respect to the vehiclein synchronization with the rotational movement (in the “couplingrange”).

Thus, with the above-described rotation/slide coupling mechanism 950,when the seat body 902 is rotated by the predetermined angle α to thedoor opening side (downward as viewed in FIG. 81), the seat body 902thereafter moves forward with respect to the vehicle (to the left asviewed in FIG. 81) in synchronization with the rotational movement.Thus, the two movements can be achieved by a single operation, so thatthe usability of this type of the rotating vehicle seat can be furtherimproved.

However, a further improvement of the rotation/slide coupling mechanism950 is desirable. As shown in FIG. 82, in the rotation/slide couplingmechanism 950, in order to achieve a smooth engagement between thepinion gear 957 and the intermediate gear 956 at the beginning of theengagement (when the seat body 902 is rotated by the angle of a from theposition facing the front of the vehicle to the door opening side), theintermediate gear 956 has a toothless portion 956 a and a shortenedtooth 956 adjacent to the toothless portion 956 a, while the pinion gear957 has normal teeth. The toothless portion 956 a is formed on theinitial engagement portion by removing one tooth.

With the above-described configuration, the rotation/slide couplingmechanism 950 can achieve a smooth engagement at the beginning ofengagement when shifting from the non-coupling range to the couplingrange. However, at the end of engagement when shifting from the couplingrange to the non-coupling range (when the seat body 902 is rotated to apoint of the angular distance of a away from the position facing thefront of the vehicle in the process of returning the seat body 902 fromthe position facing the door opening side to the position facing thefront of the vehicle), the pinion gear 957 does not engage the shortenedtooth 956 b of the intermediate gear 956. Thus, the rotational movementof the seat body 902 is not coupled to the sliding movement. As aresult, the seat body 902 is returned to the position facing the frontof the vehicle in the rotational direction while being not returnedexactly to the seated position in the rear end sliding position.

When such a malfunction occurs, for example, in the case that the slidelock mechanism 80 (see FIG. 9 of the first embodiment) that is actuatedin synchronization with the rotational movement of the seat body 902 isprovided, the slide lock mechanism 80 will be actuated in the state inwhich the seat body 902 is not returned to the rear end slidingposition. As a result, the slide lock mechanism 80 will not actuallyfunction on the rear sliding end.

The invention as described in claim 10 has been made in view of theabove problem, and its object is to provide a rotation/slide couplingmechanism in the rotating vehicle seat which can achieve a smooth andreliable engagement of each gear at the end of the engagement as well asat the beginning of the engagement.

This embodiment features a rotation/slide coupling mechanism 900 forcoupling the rotational movement and the longitudinal sliding movementof the seat body 902. The remaining components do not require anyparticular modifications and thus, such description will be omitted.

As shown in FIG. 80, a rack 938 is mounted on and along the side surfaceof a fixed longitudinal slide rail 932 on the interior side. Anintermediate gear 936 is rotatably mounted on the top surface of amoving slide rail 911 on the interior side via a support plate 935. Theintermediate gear 936 engages the rack 938. The position and length ofthe rack 938 are set such that this engagement is maintained over theentire longitudinal moving range of the seat body 902.

As shown in FIGS. 76, 78 and 79, similar to the above-described knownintermediate gear 956, the intermediate gear 936 has a toothless portion936 a formed by removing one tooth on the initial engagement portion.However, a tooth 936 b adjacent to the toothless portion 936 a is anormal tooth and is not shortened like the shortened tooth 956 b of theintermediate gear 956.

The pinion gear 906 has a circular-arc shape extending in a range ofabout 90°, similar to the known pinion gear, and no engagement teethother than a backlash prevention tooth 906 b are provided within apredetermined angular range α (about 26° in this embodiment) on theinitial engagement side (the end in the counterclockwise direction).

As shown in FIG. 77, a deformed tooth 906 a is formed by filling a gapbetween two teeth (a first tooth 906 a 1 and a second tooth 906 a 2,which the intermediate gear 936 engages first and then second,respectively, when the seat body 902 is rotated to the door openingside) so as to have a continuous shape. As shown in the drawing, the endof the deformed tooth 906 a on the side of the second tooth 906 a 2 hasthe same height as normal teeth 906 a 3, but the height is decreasedtoward the first tooth 906 a 1 that is engaged at the beginning (theside at the beginning of engagement; the left side as viewed in thedrawing).

As shown in FIG. 76, the deformed tooth 906 a has a thicknesssubstantially corresponding to the length of the toothless portion 936 aof the intermediate gear 936. Therefore, the deformed tooth 906 a fitssnugly in the toothless portion 936 a.

Further, the backlash prevention tooth 906 b is formed on the end of thepinion gear 906 which is the end of the non-coupling range. When theseat body 902 is located in the position facing the front of thevehicle, as shown in FIG. 79, the backlash prevention tooth 906 b mesheswith the intermediate gear 936, thus preventing backlash between theintermediate gear 936 and the rack 938.

With the rotation/slide coupling mechanism 900, the pinion gear 906 doesnot engage the intermediate gear 936 within the initial range of about26° at the beginning of rotation, in which the seat body 902 is rotatedfrom the initial seated position (the position facing the front of thevehicle) to the door opening side. Thus, the seat body 902 only rotateswithout moving forward (in the “non-coupling range”).

When the seat body 902 further rotates to the door opening side, thepinion gear 906 starts to engage the intermediate gear 936. Thus, theintermediate gear 936 rotates in synchronization with the rotationalmovement of the seat body 902. By being in engagement with the rack 938,the intermediate gear 936 moves forward of the vehicle while rotating.As a result, the rotating support base 910 moves forward of the vehicle,and thus the seat body 902 rotates while moving forward (in the“coupling range”).

The instant when the pinion gear 906 starts to engage the intermediategear 936 with the rotational movement of the seat body 902 to the dooropening side will now be explained. At this time, the pinion gear 906 isrotating in the direction of an arrow in FIG. 76 (in the direction ofstarting engagement). The deformed tooth 906 a is formed on the initialengagement portion of the pinion gear 906 by filling the gap between thetwo teeth (the first tooth 906 a 1 and the second tooth 906 a 2) so asto have a continuous shape. Therefore, at the beginning of engagementbetween the pinion gear 906 and the intermediate gear 936, a tooth 936 bof the intermediate gear 936 does not enter between the first and secondteeth 906 a 1 and 906 a 2, so that a reliable state of starting theengagement without tooth disengagement can be achieved. If toothdisengagement occurs between the pinion gear 906 and the intermediategear 936, the longitudinal slide lock mechanism 80 and the rotation lockmechanism 70 (see FIG. 7 of the first embodiment) will not functionproperly. However, the tooth disengagement does not occur by provisionof the deformed tooth 906 a, so that the slide lock mechanism 80 and therotation lock mechanism 70 can properly function.

Further, as shown in FIG. 77, the height of the deformed tooth 906 a ofthe pinion gear 906 is decreased from the side of the second tooth 906 a2 (normal tooth) toward the first tooth 906 a 1. Therefore, the deformedtooth 906 a engages the toothless portion 936 a without interfering withthe tooth 936 b (the tooth 936 b on the rearward side of the toothlessportion 936 a in the direction of starting the engagement). As a result,the pinion gear 906 can smoothly engage the intermediate gear 936.

The height of the deformed tooth 906 a on the side of the first tooth906 a 1 is decreased such that the deformed tooth 906 a does not engagethe tooth 936 b on the rearward side of the toothless portion 936 a inthe rotational direction, but engages a tooth 936 c on the frontwardside of the toothless portion 936 a in the rotational direction.

On the other hand, when the seat body 902 returns from the positionfacing the door opening side to the position facing the front of thevehicle, as shown in FIG. 78, the pinion gear 906 rotates clockwise. Atthis time, the end portion of the deformed tooth 906 a of the piniongear 906 on the side of the second tooth 906 a 2, engages the tooth 936b of the intermediate gear 936. Because the end portion of the deformedtooth 906 a on the side of the second tooth 906 a 2 has the same heightas normal teeth, the deformed tooth 906 a securely engages the tooth 936b of the intermediate gear 936. Therefore, the engagement of the piniongear 906 with the intermediate gear 936 is reliably maintained until theseat body 902 has returned all the way to the rear end sliding position.In this respect, in the known rotation/slide coupling mechanism 950, thepinion gear 957 does not engage the shortened tooth 956 b of theintermediate gear 956, which results in the seat body 902 not beingreturned to the rear end sliding position. Such a problem does not occurwith the rotation/slide coupling mechanism 900 of this embodiment.

The timing when the steel ball 85 is disengaged from the slide lockautomatic release plate 7 to release the slide lock (when it comes tothe relative position (b) in FIG. 9) is set to be immediately before thedeformed tooth 906 a of the pinion gear 906 engages the toothlessportion 936 a of the intermediate gear 936 by rotation of the seat body902. Specifically, within the initial range of about 26° at thebeginning of rotation of the seat body 902 from the initial seatedposition to the door opening side, the steel ball 85 abuts against theslide lock automatic release plate 7 and the cylindrical portion 83 a ofthe retainer 83 is held inserted within the lock hole 31 a (in therelative position (a) in FIG. 9). Thus, the seat body 902 is held lockedto prevent movement in the longitudinal direction.

When the seat body 902 rotates by about 26°, the steel ball 85 isdisengaged from the slide lock automatic release plate 7 to release theslide lock (in the relative position (b) in FIG. 9). Then, the retainer83 is displaced upwardly by the biasing force of the compression spring84, and thus the cylindrical portion 83 a is moved out of the lock hole31 a (in the relative position (c) in FIG. 9). Consequently, the seatbody 902 is allowed to move longitudinally (i.e. “automatic release ofthe slide lock”). Thereafter, the steel ball 85 is held pressed againstthe underside of the pinion gear 906 and thus the slide lock releasedstate is maintained until the seat body 902 reaches the sidewaysposition facing the door opening side.

On the other hand, while the seat body 902 is being rotated by about 64°from the sideways position facing the door opening side toward theseated position, the retainer 83 of the slide lock mechanism 80 is helddisplaced upwardly, so that the slide lock is released. Thus, the seatbody 902 moves rearward while rotating toward the seated position(clockwise). When the seat body 902 rotates by about 64° from thesideways position to the seated position, the seat body 902 returns tothe rearmost position in the longitudinal direction with respect to thevehicle. At the same time, the steel ball 85 is engaged with the slidelock automatic release plate 7. As a result, the retainer 83 isdepressed against the biasing force of the compression spring 84 and thecylindrical portion 83 a is inserted again into the lock hole 31 a.Thus, the seat body 902 is locked to prevent longitudinal movement inthe rearmost position (in the relative position (a) in FIG. 9).Thereafter, the seat body 902 only rotates about 26° to return to theseated position facing the front of the vehicle.

Thus, the automatic locking and unlocking of the slide lock mechanism 80is timed to the coupling of the rotation and the longitudinal movementof the seat body 902. The slide lock automatic release plate 7 isconfigured to have a proper dimension and shape and is mounted in such aposition that allows such locking and unlocking.

In the known rotation/slide coupling mechanism 950, as described above,because the pinion gear 957 does not engage the shortened tooth 956 b ofthe intermediate gear 956, the seat body 902 may be returned to theposition facing the front of the vehicle while not being returned to therear end sliding position. In this case, when the steel ball 85 in theslide lock mechanism 80 engages the slide lock automatic release plate 7and the retainer 83 is depressed, the lock hole 31 a may not yet belocated below the cylindrical portion 83 a. In such a case, the retainer83 is located between the slide lock automatic release plate 7 and thebase 31 of the longitudinal support base 30, which causes not only amalfunction of the slide lock mechanism 80 but also a malfunction of theseat body 902 in the rotational movement.

On the other hand, with the rotation/slide coupling mechanism 900 of thetenth embodiment, because the engagement between the pinion gear 906 andthe intermediate gear 936 is maintained all the way (until the seat body902 is returned all the way to the rear end sliding position), when thesteel ball 85 is engaged with the slide lock automatic release plate 7,the lock hole 31 a is reliably located below the cylindrical portion 83a. Therefore, a malfunction of the slide lock mechanism 80 as describedabove does not occur.

With the rotation/slide coupling mechanism 900 of the tenth embodiment,the toothless portion 936 a is formed on the initial engagement portionof the intermediate gear 936 (while the shortened tooth 956 b is notprovided). Further, the deformed tooth 906 a is formed on an initialengagement portion of the pinion gear 906 so as to fit in the toothlessportion 936 a of the intermediate gear 936, and the deformed tooth 906 ais shorter on the side of the first tooth 906 a 1 than the normal teeth906 a 3. Therefore, at the beginning of engagement when rotating theseat body 902 to the door opening side, the deformed tooth 906 a fitsinto the toothless portion 936 a without interference of the portion ofthe deformed tooth 906 a on the side of the first tooth 906 a 1 with thetooth 936 b of the intermediate gear 936. As a result, the pinion gear906 can smoothly engage the intermediate gear 936 without toothdisengagement.

On the other hand, at the end of the engagement to rotate the seat body902 to the interior side, because the deformed tooth 906 a on the sideof the second tooth 906 a 2 has the same height as normal teeth, thedeformed tooth 906 a securely engages the tooth of the intermediate gear936, so that the engagement of the pinion gear 906 with the intermediategear 936 is reliably maintained. Thus, the intermediate gear 936 can berotated completely to the end to thereby permit the seat body 902 to bemoved all the way back to the rear end sliding position.

As described above, with the rotation/slide coupling mechanism 900 ofthis embodiment, at the beginning of the engagement, the pinion gear 906can smoothly engage the intermediate gear 936 without toothdisengagement. At the end of the engagement, the engagement between thepinion gear 906 and the intermediate gear 936 is maintained all the wayuntil the seat body 902 is returned entirely to the rear end slidingposition. Therefore, when the seat body 902 is thereafter furtherrotated to the interior side to actuate the slide lock mechanism 80, thecylindrical portion 83 a of the retainer 83 is reliably inserted intothe lock hole 31 a. Thus, the slide lock mechanism 80 can functionproperly and reliably.

Various changes or modifications may be added to the above-describedtenth embodiment. For example, in the above embodiment, it has beendescribed that the pinion gear 906 indirectly engages the rack 938 viathe intermediate gear 936. However, it may be constructed such that apinion gear directly engages a rack without disposing the intermediategear 936 therebetween. In this case, in order to ensure matching in therotational direction and in the sliding direction of the seat body 902,although it is not shown, the rack must be mounted along the slide railon the exterior side (the lower slide rail as viewed in FIG. 80), thatis, on the opposite side of the rack 938 of the tenth embodiment.

Even in such a case in which the pinion gear directly engages the rackwithout disposing the intermediate gear 936, the same effect as thetenth embodiment can be obtained by forming a toothless portion on theinitial engagement portion of the rack and forming a deformed tooth onthe initial engagement portion of the pinion gear, which deformed toothis shorter on the initial engagement side than normal teeth.

What is claimed is:
 1. A rotating vehicle seat, comprising a rotatingsupport base for supporting a seat body in a manner that permitsrotation around a center of rotation that is located at a point that isdisplaced to a door opening side with respect to a center of a seatcushion, a longitudinal support base for supporting the rotating supportbase to permit movement in a longitudinal direction of a vehicle, andcoupling means for coupling the rotational movement and the longitudinalmovement of the seat body, said coupling means including a pinion gearmounted beneath the seat body to the interior side of said center ofrotation and a rack mounted on and extending in a longitudinal directionof said longitudinal support base, said rack engaging said pinion gearvia an intermediate gear.
 2. The rotating vehicle seat as defined inclaim 1, further comprising a lateral support base for moving the seatbody in a lateral direction of the vehicle and a stopper member forpreventing longitudinal movement of the seat body during lateralmovement of the seat body, wherein the stopper member is disposed on thelongitudinal support base to permit movement into and out of alongitudinal traveling path of the seat body, such that, when thelongitudinal support base is moved to an interior side end of thelateral support base, the stopper member moves out of the traveling pathof the seat body to thereby allowing the seat body to movelongitudinally, while, when the longitudinal support base moves from theinterior side end to the exterior side of the lateral support base, thestopper member moves into the traveling path of the seat body to therebyprevent longitudinal movement of the seat body.
 3. The rotating vehicleseat as defined in claim 1, further comprising a lateral support basefor moving the seat body in a lateral direction of the vehicle, thelateral support base being disposed between the rotating support baseand the seat body and being constructed to move the seat body to a lowerposition as the seat body moves to the outside in the lateral directionof the vehicle.
 4. The rotating vehicle seat as defined in claim 3,wherein the seat body can be detached from the lateral support base soas to be used as a wheelchair.
 5. The rotating vehicle seat as claimedin claim 3, wherein at least one of the longitudinal support base andthe lateral support base has a linear slide mechanism that consists ofan outer rail, an inner rail and a plurality of steel balls disposedbetween the outer and inner rails.
 6. The rotating vehicle seat asdefined in claim 1, further comprising a swing extending mechanism thatessentially consists of a quadric link mechanism, wherein the seat bodycan be moved lateral with respect to the vehicle by the swing extendingmechanism and wherein the seat body can be detached from the swingextending mechanism so as to be used as a wheelchair.
 7. The rotatingvehicle seat as defined in claim 1, further comprising a swing extendingmechanism that essentially consists of a quadric link mechanism, whereinthe seat body can be moved laterally with respect to the vehicle by theswing extending mechanism and wherein the seat body can be detached fromthe swing extending mechanism so as to be used as a seat of awheelchair.
 8. The rotating vehicle seat as defined in claim 1, furthercomprising a swing extending mechanism that essentially consists of aquadric link mechanism, wherein the seat body can be moved laterallywith respect to the vehicle by the swing extending mechanism and whereinan electric motor is used as a driving source for the swing extendingmechanism, the motor having a threaded shaft oriented to the front ofthe seat.
 9. The rotating vehicle seat as defined in claim 1, furthercomprising a swing extending mechanism that essentially consists of aquadric link mechanism, wherein the seat body can be moved laterallywith respect to the vehicle by the swing extending mechanism, andfurther comprising a swing lock mechanism that functions only when animpact is applied while the vehicle is running, so as to prevent theseat body from moving forward with respect to the vehicle by the swingextending mechanism, while, in normal operations when the vehicle isstopped, permitting the seat body to be moved laterally with respect tothe vehicle.
 10. The rotating vehicle seat as defined in claim 1,further comprising a swing extending mechanism that essentially consistsof a quadric link mechanism, wherein the seat body can be movedlaterally with respect to the vehicle by the swing extending mechanism,and further comprising a swing lock mechanism that functions to preventthe seat body from being moved forward with respect to the vehicle bythe swing extending mechanism with the seat body is located in aposition facing the front of the vehicle, while permitting the seat bodyto be moved laterally with respect to the vehicle by the swing extendingmechanism when the seat body is rotated to the door opening side. 11.The rotating vehicle seat as defined in claim 1, wherein thelongitudinal support base includes a linear slide mechanism thatconsists of a fixed rail, a moving rail and a plurality of rollingelements disposed between the fixed rail and the moving rail, andwherein a guide rail is provided on and along one side of the movingrail, which is opposite to the side of the fixed rail and supports themoving rail to permit the moving rail to slide.
 12. The rotating vehicleseat as defined in claim 11, further including a hook that is providedon a travelling path of the moving rail such that a rear end portion ofthe moving rail can slide into and out of the hook.
 13. The rotatingvehicle seat as defined in claim 1, wherein a toothless portion isformed on an initial engagement portion of the intermediate gear and adeformed tooth is formed on an initial engagement portion of the piniongear and engages the toothless portion, the deformed tooth having athickness substantially corresponding to a length of the toothlessportion, a height of the deformed tooth on a front end in a direction ofstarting engagement being smaller than normal teeth, and a height of thedeformed tooth on a rear end in the direction of starting engagementbeing equal to normal teeth.